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Showing posts with label Electronics. Show all posts
Showing posts with label Electronics. Show all posts

Wednesday, 18 December 2019

Smart contact lens recharges wirelessly without removing it from user's eye


Electronic Contact Lenses

The robotic contact lenses have promised true superpowers to humans, the vision of laser beams to a telescopic zoom built into the eye.

This technology, still in the developmental stage, has now received a huge boost: a wireless rechargeable power source, meaning all equipment installed on the contact lens can be fueled and continue working without even being removed from the user's eye.

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Instead of a traditional battery, Jihun Park and colleagues at Yonsei University in South Korea used a printable supercapacitor, making it easy to attach to the contact lens.

In addition to the rechargeable supercapacitor, the prototype has an antenna and a red LED, all working without obscuring the user's vision. It sounds like science fiction, but the device has already been tested by a volunteer and worked perfectly.

Wireless rechargeable supercapacitor scheme.

Rechargeable supercapacitor

The supercapacitor is made of carbon electrodes and a solid state polymer electrolyte. Each material is dispersed in a solvent and printed as separate layers on the lens. A high-precision technique called microscale direct ink writing allows the supercapacitor to be printed outside the area covering the user's pupil, meaning that the device does not interfere with vision.

The flexible wireless power transfer unit - comprising an ultra-thin rectifier circuit and an antenna made of nanofibers and silver nanowires - allows the contact lens to recharge at a distance of about 1 cm from a transmitting coil.



The rechargeable contact lens was tested on live rabbits and finally on a human - during the 10 minute test, no damage was detected in the volunteer's eye.


Bibliography:

Article: Printing of wirelessly rechargeable solid-state supercapacitors for soft, smart contact lenses with continuous operations

Authors: Jihun Park, David B. Ahn, Joohee Kim, Byeong-Soo Bae, Sang-Young Lee, Jang-Ung Park

Magazine: Science Advances

Vol .: 5, no. 12, eaay0764
DOI: 10.1126 / sciadv.aay0764

Tuesday, 17 December 2019

Magnonica promises 1,000 times faster processors - and no overheat

Future devices like this one, based on magnet torque, will be faster, consume less power and will not overheat.

Magnetic wave computing

Singapore researchers have developed a revolutionary way to encode computational information without using electric current.

This will allow you to build faster appliances that can use energy efficiently without overheating, as well as more energy efficient logic and memory devices.

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Instead of adopting the traditional electron injection methods used in traditional electronics, Yi Wang and his colleagues used "spin waves" to toggle bit magnetization.

Spin waves are propagations of disturbances in the crystal structure of magnetic materials. These waves are typically described as quasiparticles, known as " magnons ", and establish a kind of link between "electro" and "magnetism" . Just as the spin of electrons gave rise to spintronics , it was long hoped that magnons could be explored technologically, creating a magnetic.



In addition to everything operating at room temperature, the operating frequency of spin waves is in the terahertz range, at least a thousand times faster than the gigahertz of today's processors. Terahertz devices will be able to transmit data at significantly higher speeds than currently possible.

Comparison between the operation of one component based on electron spin (spintronic) and another based on magnetic (magnetic) spin.

Magnetic

The team built a two-layer component consisting of an antiferromagnetic magnet transport channel and a spin source in the form of a topological insulator . In an unprecedented feat, they successfully demonstrated the switching of one-bit spin-wave magnetization in the ferromagnetic layer with high efficiency.

The new spin-erase bit-based switching scheme relies on the moving charges of electrons. Therefore, circuits using this mechanism should have significantly lower Joule power and heat dissipation than equivalent electronics - in simpler terms, processors that don't heat up and use very little energy, allowing a new wave of speed up in computing. and portable devices with much longer batteries.

"Spin waves (magnons) can transmit information even on insulating [materials] without involving moving loads. This unique property allows for longer spin propagation but less dissipation compared to electron spins.

"Then we can control the magnetization if we transfer the spin information from the magnons to the local magnetization, which can be understood as a 'magnet torque'. Just as a linear force is an impulse or a traction, a torque can be considered as a Thus, this new way of manipulating magnetization can be used for future logic and memory devices.



"We know that electric spin torque has opened the era for applications of spintronic devices such as random access magnetic memories (MRAMs). We believe that our description of the new magnetization torque scheme for magnetization switching is a revolutionary idea in spintronics. "It will reinvigorate not only a new area of ​​research in magnetic, but also practical, magnon-operated devices," said Wang Yi of the National University of Singapore.

Next, the team plans to work to further increase the efficiency of the magnet torques and start building the various magnetic components that can have the same functionality as the electronics, but without involving any electrical parts.


Bibliography:

Article: Magnetization switching by magnon-mediated spin torque through an antiferromagnetic insulator

Authors: Yi Wang, Dapeng Zhu, Yumeng Yang, Kyusup Lee, Rahul Mishra, Gyungchoon Go, Se-Hyeok Oh, Dong-Hyun Kim, Kaiming Cai, Enlong Liu, Shawn D. Pollard, Shuyuan Shi, Jongmin Lee, Kie Leong Teo, Yihong Wu, Kyung-Jin Lee, Hyunsoo Yang

Journal: Science

Vol .: 366, Issue 6469, pp. 1125-1128
DOI: 10.1126 / science.aav8076

Friday, 13 December 2019

Liquid crystal microlenses capture 4D images

The polarization of light brings a new world of information.

4D images

While most images captured by a camera lens are still flat and two-dimensional, more and more 3D imaging technologies are providing the crucial depth context for medical and scientific applications.

An additional step is in 4D images, whose additional dimension refers to information about light polarization.

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This may open even more application possibilities, but the first prototypes of this technology, such as a 4D microscope , consist of bulky, expensive and complicated equipment.

Now researchers at Nanjing University in China have developed liquid crystal microlenses that can reveal 4D information in a single photographic shot.

The microlenses do not have to be "fabricated" - they assemble themselves thanks to the liquid crystal.

Polarized light

Polarized light contains waves that oscillate in a single plane, while unpolarized light, such as that of the sun, contains waves that move in all directions. Light can become polarized upon reflection of objects, and detecting such light can reveal information that is not available just by looking at the object - for example, cancer cells may reflect polarized light differently from healthy tissues.

Ling-Ling Ma and his colleagues wanted to develop a portable, inexpensive, easy-to-use microlens to simultaneously capture 3D space information plus polarization producing 4D images.

They succeeded using liquid crystals. With a self-assembly process, they modeled microlens arrays in concentric circles, creating a new type of flat lens .

Microlenses capture light reflected by the object differently depending on the distance from the object (depth) and the direction of polarized light, producing 4D information in a single shot.



Although the resolution still needs to be improved, the technique could be used for medical imaging, telecommunications, screens and monitors, remote sensing and even encryption, the researchers say.


Bibliography:

Article: Self-Assembled Asymmetric microlenses for Four-Dimensional Visual Imaging

Authors: Ling-Ling Ma Sai-Bo Wu, Wei Hu, Chao Liu, Peng Chen, Hao Qian, Yandong Wang Lifeng Chi, Yan-qing Lu

Magazine : ACS Nano

DOI: 10.1021 / acsnano.9b07104

Saturday, 23 November 2019

Structured light allows communication with infinite Photonic alphabet

Illustration shows the creation of hybrid interlaced photons combining polarization with a twisted light pattern that carries orbital angular momentum . This structured light allows you to use quantum protocols to create a larger coding alphabet, more security and better noise resistance.


Structured light

The creation of Structured Light beams - light in exotic patterns such as spirals - not only revealed a strange new world of light, but also opened new fields of technological exploration for photonics .

And it seems that these application possibilities have not even been scratched.

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Two South African researchers have already shown that it is possible to exploit helical beams of light to create an alphabet, which promises not only greater security and robustness in communications, but also a new way to explore the physics behind quantum computers. .

"What we really want is to do quantum mechanics with light patterns. By that we mean that light comes in a variety of patterns that can be differentiated - like our faces," explained Andrew Forbes of the University of Witwatersrand.


Since light patterns can be distinguished from each other, they can be used as an alphabet form. "The cool thing is that there is, at least in principle, an infinite set of patterns, so an infinite alphabet is available," said Forbes.

Different patterns of structured light - the "letters" of the infinite photonic alphabet.

Multidimensional States

Traditionally, quantum protocols have been implemented with light bias, which has only two values, which means a maximum photon information capacity of just 1 bit - remembering that one bit per photon is already incredibly better than the floods of light. electrons used today. Using structured light patterns as an alphabet, in turn, the information capacity is much greater, not to mention the gains in safety and noise resistance.

"Light patterns are a path to what we call large states," continues Forbes. "They are large because many standards are involved in the quantum process. Unfortunately, the toolkit for managing these patterns is still underdeveloped and requires a lot of work."

That's why he and his colleague Isaac Nape began working with hybrid states, which combine the traditional use of polarization with structured modes of light.

"It turns out that many protocols can be implemented efficiently with simpler tools, combining polarized patterns for the best of both worlds," said Forbes. "Instead of two pattern dimensions, hybrid states allow access to multidimensional states, for example an infinite set of two-dimensional systems. This seems to be a promising way to truly make a quantum lattice based on light patterns come true."




Bibliography:

Article: Quantum mechanics with patterns of light: Progress in high dimensional and multidimensional entanglement with structured light

Authors: Andrew Forbes, Isaac Nape

Magazine: AVS Quantum Science

DOI: 10.1116 / 1.5112027

A strange new world of light


Structured light

Over the past ten years, the physical developed nanostructured materials that can produce light beams completely out of the standard, which exhibit unusual behaviors such as spiral bending , corkscrew shape or that share as a Y .

These so-called structured light beams are not only revealing unknown things about the physics of light, they also have a wide range of practical applications, from super resolution images to microscopes and telescopes, to light-beam molecular manipulation and communications. by light without optical fibers.

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Now researchers have developed a tool that generates new, more complex light states in a completely different and configurable way.

"We have developed a metasurface that is a new tool for studying unpublished aspects of light. This optical component enables much more complex operations and allows researchers to not only explore new states of light but also new applications for structured light," said the professor. Federico Capasso, from Harvard University, USA.

Angular momentum and polarization

The metasurface connects two aspects of light: orbital angular momentum and circular polarization (or angular rotation pulse). In comparison to a planet, orbital momentum describes how the planet orbits the sun and circular polarization describes how the planet rotates about its own axis (rotation).

Light bias could already be used to control the size and shape of these exotic beams, but the connection was limited because only certain polarizations could be converted at certain orbital moments.

The new metamaterial significantly widens this connection. It can be designed so that any input bias can result in any orbital angular momentum output. In other words, any polarization can produce any kind of structured light, from spirals and corkscrews to vortices of any size.

Another great advantage is that the metasurface is multifunctional and can be programmed so that a polarization results in one vortex and a different polarization results in another completely different vortex.

Examples of structured light showing cross sections of beams.


Applications

Potential applications of this device include molecular manipulation and optical tweezers, which use light to move molecules and nanoparticles - the orbital momentum of light is strong enough to rotate and move microscopic particles.

Other fields of application include high resolution images, light beams for quantum computing, free space optical communication, and new light states in lasers.


Bibliography:

Article: Arbitrary spin-to-orbital angular momentum of light conversion

Authors: Robert C. Devlin, Antonio Ambrosio, Noah A. Rubin, JP Balthasar Mueller, Federico Capasso

Magazine: Science

Vol .: eaao5392

DOI: 10.1126 / science.aao5392


Tuesday, 25 June 2019

Negative capacitor takes power only where it is needed

This image shows the motion of the domain wall (ac and bd) in a capacitor when a charge is added to one side (c). The resulting redistribution of the domain wall causes a negative capacitive effect

Negative capacitor

After exploring the negative capacitance to create a transistor that spends less energy, researchers are now exploring the strange phenomenon to create new ways of storing and redistributing energy on the scale of microchips.

Igor Lukyanchuk and his colleagues from the USA, France, and Russia created a static and permanent negative capacitor, a component that up to 10 years ago was seen as a violation of the laws of physics.

While the previously proposed projects for negative capacitors operated on a temporary and transient basis, the new concept functions as a steady-state reversible device.

In traditional capacitors, the component's electrical voltage is proportional to its stored electrical charge - increasing the amount of stored charge increases the voltage. In negative capacitors, the opposite happens - increasing the amount of charge decreases the voltage.

Since the negative capacitor is a part of a larger circuit, this does not violate the law of energy conservation.

Electricity on demand

The team found that by pairing a negative capacitor in series with a standard positive capacitor, it is possible to locally increase the voltage on the positive capacitor to a point higher than the total system voltage.

In this way, it becomes possible to distribute electricity to regions of a circuit that require more voltage, while the bulk of the circuit remains running at low voltage.

This allows to rationalize the use of electricity inside chips and electronic circuits, using only what is strictly necessary, while still meeting the variable demands of each part of the circuit.

With this, it becomes possible to build circuits that consume less energy - the battery lasts longer - and heat less.



Bibliography:

 Harnessing ferroelectric domains for negative capacitance
I. Lukyanchuk, Y. Tikhonov, A. Sené, A. Razumnaya, VM Vinokur
 Nature Communications Physics Vol .: 2, Article number: 22
DOI: 10.1038 / s42005-019-0121-0

Monday, 24 June 2019

Superefficient memory for future computers uses T-rays

The necktie structure acts as an antenna to capture the T rays and change the state of the spin. [Image: Schlauderer et al. - 10.1038 / s41586-019-1174-7]

Data recording with T-rays

A team from Germany, Russia and the Netherlands was able to reverse the magnetic polarization of a material in the smallest time scales ever obtained, at a minimal energy cost.

When you take into account that 3% of all electricity produced in the world is already spent on data centers - the so-called cloud - any gain in the storage efficiency of each bit of information can make a big difference to the economy and the environment environment. This is one of the great objectives of the field of spintronics .

Computers store data in bits that alternate between two basic states, interpreted as zeros and ones. Remagnetizing the bit, making it change state, requires a lot of energy - and it's not as fast as we'd like.

The team developed a route for the ultrafast spinning of the spin in a material called thulium orthoferrite, one of the elements of the rare earth family.

The great news is that the switching is done by T rays, or terahertz radiation .

Picoseconds

The new technique was possible because there seems to be a special connection between the spin states and the electrical component of a T-ray pulse. This allowed us to remagnetize the memory bits faster and more efficiently than is possible using pulses of magnetic field.

The terahertz pulses last in the range of the picoseconds, which corresponds to a cycle of light oscillation, that is, it is much faster than any current technology.

The switching of each spin was completed in only 3 picoseconds and almost no dissipation of energy - the team ensures that the dissipation of energy is at the minimum level of loss imposed by the fundamental laws of thermodynamics.

The next step is to move from proof of concept to components closer to end use.


Bibliography:

 Temporal and spectral fingerprints of ultrafast all-coherent spin switching
S. Schlauderer, C. Lange, S. Baierl, T. Ebnet, CP Schmid, DC Valovcin, AK Zvezdin, AV Kimel, RV Mikhaylovskiy, R. Huber
 Nature Vol. : 569, pages 383-387
 DOI: 101038 / s41586-019-1174-7

Sunday, 23 June 2019

The invention of universal computer memory could solve the digital technology energy crisis

The device could replace the $100bn market for Dynamic Random Access Memory (DRAM), which is the ‘working memory’ of computers, as well as the long-term memory in flash drives

A new type of computer memory which could solve the digital technology energy crisis has been invented and patented by Lancaster scientists.

The electronic memory device – described in research published in Scientific Reports – promises to transform daily life with its ultra-low energy consumption.

In the home, energy savings from efficient lighting and appliances have been completely wiped out by increased use of computers and gadgets, and by 2025 a ‘tsunami of data’ is expected to consume a fifth of global electricity.

But this new device would immediately reduce peak power consumption in data centres by a fifth.

It would also allow, for example, computers which do not need to boot up and could instantaneously and imperceptibly go into an energy-saving sleep mode – even between key stokes.

The device is the realisation of the search for a “Universal Memory” which has preoccupied scientists and engineers for decades.

Physics Professor Manus Hayne of Lancaster University said: “Universal Memory, which has robustly stored data that is easily changed, is widely considered to be unfeasible, or even impossible, but this device demonstrates its contradictory properties.”

A US patent has been awarded for the electronic memory device with another patent pending, while several companies have expressed an interest or are actively involved in the research.

The inventors of the device used quantum mechanics to solve the dilemma of choosing between stable, long-term data storage and low-energy writing and erasing.

The device could replace the $100bn market for Dynamic Random Access Memory (DRAM), which is the ‘working memory’ of computers, as well as the long-term memory in flash drives.
While writing data to DRAM is fast and low-energy, the data is volatile and must be continuously ‘refreshed’ to avoid it being lost: this is clearly inconvenient and inefficient. Flash stores data robustly, but writing and erasing is slow, energy intensive and deteriorates it, making it unsuitable for working memory.

Professor Hayne said: “The ideal is to combine the advantages of both without their drawbacks, and this is what we have demonstrated. Our device has an intrinsic data storage time that is predicted to exceed the age of the Universe, yet it can record or delete data using 100 times less energy than DRAM.”



Bibliography:

Room-temperature Operation of Low-voltage, Non-volatile, Compound-semiconductor Memory Cells
 Ofogh Tizno, Andrew R. J. Marshall, Natalia Fernández-Delgado, Miriam Herrera, Sergio I. Molina, Manus Hayne. . 
Scientific Reports, 2019; 9 (1) 
DOI: 10.1038/s41598-019-45370-1

Thursday, 20 June 2019

Brazilians optimize promising material for flexible electronics

Order of polythiophene: (a) schematic illustration of the experimental process; (bec) ordered polythiophene. Beside a preview of the original, messy material. [Image: Portone et al. - 10.1038 / s41598-019-43719-0]

Flexible electronics

Flexible electronics, or organic electronics , in which components and electronic circuits are made of plastic, is one of the major technological trends today.

It should enable thin and flexible devices and optoelectronic devices - which provide, detect and control light - extremely lightweight and foldable.

There is much research being done for this, an example of which has just been reported by Alberto Portone and a team from USP (University of São Paulo) and the Institute of Nanoscience of Italy.

The team was able to improve the optical and electronic properties of polythiophene. Due to its lightness, flexibility and ease of processing, polythiophene is an organic material which is very attractive because of its mechanical properties and because it is a plastic that carries heat .

"The configuration of polythiophene, if it is processed in the most common way, by spin casting , is quite disorderly, compromising its optical and electronic performance. In our work, the proposal was to order the material, making it much more selective in the emission and absorption of light, "said Professor Marília Junqueira Caldas.


Ordered polythiophene

The arrangement of the organic optoelectronic material was obtained in a surprisingly simple manner. A drop of the polymer in solution was deposited on a support. As it evaporated, a kind of grid was applied over the drop, causing it to present a sequence of parallel grooves. The striation ordered the internal structure of the material.

"With the ordering, the polymer began to absorb and emit light in a very predictable way, enabling stimulated emission of light at frequencies not available in the disordered film.It was a gain in selectivity.In addition, the resulting device was much lighter than others with similar function, based on overlays of various types of semiconductors, "said Marília.

"Our approach demonstrates a viable strategy for directing optical properties through structural control. Optical gain observation opens the possibility of using polythiophene nanostructures as building blocks for organic optical amplifiers and active photonic devices," wrote the team in its article.



Bibliography:

 Tailoring optical properties and stimulated emission in nanostructured polythiophene
Alberto Portone, Lucia Ganzer, Federico Branchi, Rodrigo Ramos, Marília J. Caldas, Dario Pisignano, Elisa Molinari, Giulio Cerullo, Luana Persano, Deborah Prezzi, Tersilla Virgili

 Nature Scientific Reports
 Vol. : 9, Article number: 7370 
 DOI: 10.1038 / s41598-019-43719-0

Physicists predict quantum leap and save Schrodinger's cat

Physicists say it is possible to predict the quantum leap, contrary to a theory accepted for decades. [Image: Kat Stockton]


How to Save the Cat from Schrodinger

A team of physicists from Australia, USA and France discovered how to save Schrodinger's famous cat , the symbol of quantum superposition and the unpredictability of nature on an atomic scale.

The discovery will allow researchers to create an early warning system for quantum leaps that occur between qubits, the fundamental elements of quantum computing , and cause them to lose their data.

Schrodinger's cat is a well-known paradox, used to illustrate the concept of superposition - the ability of a particle to exist simultaneously in two different states - and the unpredictability, well expressed in the well-known Heisenberg Uncertainty Principle .

To illustrate these principles, physicist Erwin Schrodinger (1887-1961) devised a mental experiment in which a cat would be placed in a sealed box, along with a radioactive source and a poison that would be released if an atom of the radioactive substance decayed - decay is a typical quantum phenomenon.

The superposition theory suggests that until someone opens the box, it is not possible to know whether the atom has decayed or not - in other words, the cat will be alive and dead at the same time in a superposition of states, as well as the particle that determines your destiny. Opening the box to observe the cat causes it to abruptly change its quantum state, which will then collapse into a dead or alive situation.

Quantum leap

Now, Zlatko Minev and his colleagues decided to take a closer look at the actual functioning of the mechanism that dictates this change of state, the famous quantum leap. The quantum leap is the discrete (non-continuous) and random change in the state of an atomic particle, which only "realizes" when it is observed, when its wave function collapses.

What they have discovered is that it is possible to anticipate the quantum leap that will determine the changing state of the decaying radioactive particle and the action of releasing the venom. More than that, it is possible to act in real time to save the cat, which overthrows decades of a fundamental dogma of quantum physics.

The experiment showed an increase in coherence during the jump - rather than the decoherence - even when the phenomenon was observed, which typically destroys quantum coherence. With this, it is possible to reverse the jump.

Thus, the results contradict the view established by the Danish physicist Niels Bohr (1885-1962), stating that quantum leaps are neither abrupt nor as random as previously thought.

The experiment consisted in monitoring an artificial superconducting atom using three microwave generators radiating the atom, which is trapped in a 3D cavity made of aluminum. [Image: Minev et al. - 10.1038 / s41586-019-1287-z]

Quantum computers

For a tiny object, such as an electron, a molecule, or an artificial atom containing quantum information - that's why they function as qubits - a quantum leap is the sudden transition from one discrete energy state to another.

Because in the development of quantum computers, qubit jumps manifest themselves as errors in calculations - the change of state means that the qubit has lost its data - this finding simply says that it is possible to act against these errors, canceling them at source, so they occur.

This is also a crucial point for theory, researchers say, because although quantum jumps appear discrete and random in the long run, reversing a quantum leap means that the evolution of the quantum state has a deterministic character in part, and random - the jump always occurs in the same predictable way from its random starting point.

"The quantum leaps of an atom are somewhat analogous to the eruption of a volcano, and they are completely unpredictable in the long run. However, with proper monitoring, we can detect early warning of an impending disaster and act before it occurs , "said Minev.


Bibliography:

 To catch and reverse quantum jump mid-flight Zlatko K. Minev, Shantanu O. Mundhada, Shyam Shankar, Philip Reinhold, Ricardo Gutiérrez-Jáuregui, Robert J. Schoelkopf, Mazyar Mirrahimi, Howard J. Carmichael, Michel H. Devoret Nature
DOI: 10.1038 / s41586-019-1287-z https://arxiv.org/abs/1803.00545

Tuesday, 18 June 2019

3D magnetic interactions can lead to new forms of computing

The magnetic moment of the electrons (spin) interacts in a very peculiar way, allowing to exchange information. [Image: University of Glasgow]

Communication

A new form of magnetic interaction that takes a phenomenon hitherto seen as uniquely two-dimensional to the third dimension promises to open up a host of new possibilities for data storage and advanced computing.

Amalio Pacheco and his colleagues at the University of Glasgow in Scotland found a way to pass information from a series of tiny magnets arranged in an ultra thin film to magnets in a second film placed in parallel.

This adds an extra dimension - literally and metaphorically - to spintronics , the field of science devoted to the storage, retrieval, and processing of data using the magnetic moment, known as spin, of electrons.

Spintronics

You have certainly toyed with a pair of magnets, checking how opposing poles attract and similar ones repel. While this is true on our human scale, the way the magnets interact undergoes some significant changes as the magnets shrink - at the nanoscale, this includes the possibility of attracting and repelling each other at angles of up to 90 degrees, not just directly.

This is one of the pivots of spintronics, whose discovery won the Nobel Prize in Physics in 2007 . The benefits of these spin-off systems include low power consumption, high storage capacity and greater robustness.

Now spintronics emerges as an even more promising force, failing to be confined to a single plane. The ability to exchange information between layers adds new storage and computing potential.

"It's a bit like adding an extra note on a musical scale - it opens up a whole new world of possibilities, not just for processing and storing conventional information, but potentially for new forms of computing that we do not even think about yet," said Amalio Pacheco.

The explored phenomenon is known as chiral spin interaction. [Image: Pacheco et al - 10.1038 / s41563-019-0386-4]


3D Spintronics

The transmission of information between layers depends on what is known to physicists as chiral spin interactions, a type of magnetic force that favors a specific sense of rotation in neighboring magnets. This mechanism has already been explored, for example, to create skyrmions , another type of superpromising nanoscale magnetic object, since magnetic computation overcomes Boolean logic thousands of times .

Pacheco assembled a multilayer system consisting of ultrathin magnetic films separated by non-magnetic metal spacers. The structure of the system, and an accurate adjustment of the properties of each layer and its interfaces, creates unusual magnetic configurations, where the magnetic field of the two layers forms angles between zero and 90 degrees.

Unlike the multilayer magnets already created, the sandwich created by the team presents a predilection for clockwise configurations, a signal that there is a chiral spin interaction between the two magnetic layers.

This breaking of rotational symmetry was observed at ambient temperature and under standard environmental conditions, justifying the team's enthusiasm with the possibility of creating topologically complex 3-D magnetic configurations in spintronic technologies.


Bibliography:

Symmetry-breaking interlayer Dzyaloshinskii-Moriya interactions in synthetic antiferromagnets
Amalio Fernández Pacheco, Elena Vedmedenko, Fanny Ummelen, Rhodri Mansell, Dorothée Petit, Russell P. Cowburn
Nature Materials
DOI: 10.1038 / s41563-019-0386-4

Monday, 17 June 2019

Transistor saves 4 bits and bridges with quantum computing



Transistor that stores 4 bits

Engineers at the University of Texas, USA, have created a multivalued transistor, that is, a transistor that can hold more values ​​than the traditional 0 and 1.

With the difficulty of further miniaturizing transistors - the latest 10-nanometer transistors are only 30 atoms wide - the industry has shown increasing interest in so-called multivalued logic , or multi- bit logic, where each component can hold various values .

Another advantage of expanding binary language is that with each transistor encoding more information, the path to neuromorphic computation materializes , which works by mimicking the human brain. Efforts in this direction have so far focused on another family of emerging electronic components, the memoristores .

But Lynn Lee and her colleagues were able to fabricate the traditional electronic component suitable for implementing plurivalent logic, a feat that has been pursued for decades by various university and business teams.

"The concept of multi-value logic transistors is not new, and there have been many attempts to manufacture these components. We have succeeded," said Professor Kyeongjae Cho, the team's coordinator.

Multivalued Transistor

The multivalued, or multi-valent, transistor has as main components two forms of zinc oxide, combined to form a composite nanowire, which is then incorporated together with layers of other materials to form a super-grid. A superrede is a structure formed by different elements, as opposed to the atomic network of a crystal, formed by a single element - a gold diamond is an example of superrede.

While conventional transistors work with a switch - a transistor is on or off, which translates into 0s and 1s of binary language - the multivalued transistor can store two other intermediate signals.

This is possible because zinc oxide is a phase change material, which means that it can take on at least two atomic structures: crystalline or amorphous. Considering these two structures in the two forms of zinc oxide used, plus the on / off, it is possible to save up to four bits.

But the team does not consider the work to be finished: "Zinc oxide is a well-known material that tends to form crystalline solids and amorphous solids, so it was an obvious choice to start with, but it may not be the best material. step will be to analyze how this behavior is universal among other materials, while we try to optimize the technology, "Cho said.


Bridge between electronic computers and quantum computers

The effort is well worth it because, in addition to solving the challenge of miniaturizing transistors and being compatible with today's technology, multivalued logic bridges current electronic computers with future quantum computers , where qubits can hold continuous values .

"The transistor is a very mature technology and quantum computers are far from being marketed. There is a huge gap," said the researcher. "So how do we move from one to the other? We need some kind of evolutionary path, a bridge technology between binary degrees and infinite degrees of freedom." Our work is still based on the current technology of electronic components, so it's not so revolutionary in quantum computing, but it is evolving in that direction. "

Cho adds that after finding a more efficient material than zinc oxide, the next natural step will be to interconnect multivalued transistors with a quantum processor.


Bibliography:

ZnO composite nanolayer with mobility edge quantization for multi-value logic transistors Lynn Lee, Jeongwoon Hwang, Jin Won Jung, Jongchan Kim, Ho-In Lee, Sunwoo Heo, Minho Yoon, Sungju Choi, Nguyen Van Long, Jinseon Park, Jae Won Jeong, Jiyoung Kim, Kyung Rok Kim, Dae Hwan Kim, Seongil Im, Byoung Hun Lee, Kyeongjae Cho, Myung Mo Sung
Nature Communications
Vol. 10, Article number: 1998
DOI: 10.1038 / s41467-019-09998-x