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

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.


 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 .


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.


 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.”


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.


 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.


 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

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]


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.


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.


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.


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