Researchers achieve robust superconductivity in high magnetic fields using unique 1D system

An international team of researchers, led by the University of Manchester, has achieved robust superconductivity in high magnetic fields using a newly created one-dimensional system. Achieving superconductivity in the quantum Hall regime has been a longstanding challenge, which this recent work aimed to address. 

The team followed the conventional route where counterpropagating edge states were brought into close proximity to each other. However, this approach was found to be limited. “Our initial experiments were primarily motivated by the strong persistent interest in proximity superconductivity induced along quantum Hall edge states,” explained University of Mnchester's Dr. Barrier, the paper’s lead author. “This possibility has led to numerous theoretical predictions regarding the emergence of new particles known as non-abelian anyons.”

Read the full story Posted: Apr 26,2024

Graphene and tungsten diselenide combination can boost superconductivity

Researchers from California Institute of Technology (Caltech) and Japan's National Institute for Materials Science have shown that when tungsten diselenide is added to graphene, graphene's electrical properties can be enhanced.

When two or more graphene sheets are stacked on top of each other, the resulting material can exhibit vastly different electronic properties depending on the alignment of those sheets in relation to one another. For instance, when the second sheet of graphene is "twisted" by just 1.05 degrees (a value known as the "magic angle") in relation to the sheet it is laid on top of, the resulting stack can be either a superconductor that conducts electricity with absolutely no resistance whatsoever or an insulator that completely blocks the passage of electricity. Research conducted in 2022 shows that even untwisted graphene bilayers can exhibit superconductivity. Untwisted bilayers of graphene are easier to fabricate in bulk than their twisted counterparts, but the superconductive state in these untwisted bilayers is more delicate, harder to tune, and only occurs at temperatures that are about a hundred times lower than in twisted structures (such temperatures typically can only be achieved through the use of liquid helium). The recent research shows a way to significantly improve upon this fragile superconductivity with tungsten diselenide.

Read the full story Posted: Feb 24,2023

Researchers gain new insight on the role of quantum geometry in allowing 'magic angle graphene' to become a superconductor

Researchers from Ohio State University, The University of Texas at Dallas and Japan's National Institute for Materials Science have reported new evidence of how graphene, when twisted to a precise angle, can become a superconductor, moving electricity with no loss of energy.

The team announced their finding of the key role that quantum geometry plays in allowing this twisted graphene to become a superconductor.

Read the full story Posted: Feb 21,2023

Researchers achieve nanometer resolution measurement of the flow of electrons in graphene

Scientists at the University of Wisconsin-Madison and Japan's National Institute for Materials Science have directly measured, for the first time at nanometer resolution, the fluid-like flow of electrons in graphene. The results could have applications in developing new, low-resistance materials, where electrical transport would be more efficient.

Graphene is a pure electrical conductor, making it an ideal material to study electron flow with very low resistance. Here, the researchers intentionally added impurities at known distances and found that electron flow changes from gas-like to fluid-like as temperatures rise.

Read the full story Posted: Feb 19,2023

Researchers find superconductivity that can be turned on and off in "magic angle" graphene

Researchers at MIT and National Institute for Materials Science in Tsukuba, Japan, have found a new and intriguing property of “magic-angle” graphene: superconductivity that can be turned on and off with an electric pulse, much like a light switch.

The discovery could lead to ultrafast, energy-efficient superconducting transistors for neuromorphic devices — electronics designed to operate in a way similar to the rapid on/off firing of neurons in the human brain.

Read the full story Posted: Jan 29,2023

Skoltech team patents method for defect-free graphene for flexible transparent electronics

Skoltech researchers have patented a method that enables producing arbitrarily shaped functional graphene components on a transparent substrate with 100-nanometer resolution, which could be especially suited for flexible and transparent electronics. The new approach reportedly helps avoid defects that arise during graphene transfer between substrates and strongly affect the material’s quality.

“Flexible and transparent electronics is typically associated with wearable biosensors that monitor vital signs, such as heart rate, breathing, and blood oxygenation, and relay them to a smartphone or fitness band,” Skoltech PhD student Aleksei Shiverskii, one of the inventors, said. “An affordable and efficient technology that at first may seem impractical soon becomes a ubiquitous and indispensable appliance, like a bluetooth electric kettle or a wifi vacuum cleaner. I believe that someday flexible and transparent electronics will become a fixture, too.”

Read the full story Posted: Nov 22,2022

Researchers detect 'twistons' that assist the magic angles necessary for superconductivity in trilayer graphene

Researchers from Columbia University, Harvard University, Japan's National Institute for Materials Science and Austria's University of Innsbruck have studied the structural and electronic properties of twisted trilayer graphene using low-temperature scanning tunneling microscopy at twist angles for which superconductivity has been observed.

The discovery of superconductivity in two layers of graphene arranges in the "magic angle" of 1.1 degrees has become quite famous. With just two atom-thin sheets of carbon, researchers discovered a simple device to study the resistance-free flow of electricity, among other phenomena related to the movement of electrons through a material. Adding a third layer of graphene improves the odds of finding superconductivity, but the reason was unclear. Now, the researchers of the new study reveal new details about the physical structure of trilayer graphene that help explain why three layers are better than two for studying superconductivity.

Read the full story Posted: Apr 10,2022

Researchers deepen understanding of unconventional superconductivity in trilayer graphene

Researchers from Science and Technology (IST) Austria, in collaboration with scientists from the Weizmann Institute of Science in Israel, have developed a theoretical framework of unconventional superconductivity, which addresses the questions raised by earlier work that detected unique superconductivity in 'magic angle' trilayer graphene.

Superconductivity relies on the pairing of free electrons in the material despite their repulsion arising from their equal negative charges. This pairing happens between electrons of opposite spin through vibrations of the crystal lattice. Spin is a quantum property of particles comparable, but not identical to rotation. The mentioned kind of pairing is the case at least in conventional superconductors. "Applied to trilayer graphene," co-lead-author from IST, Areg Ghazaryan, points out, "we identified two puzzles that seem difficult to reconcile with conventional superconductivity."

Read the full story Posted: Dec 12,2021

Researchers develop ultra-efficient 'clean' technique to control the properties of graphene

Researchers from Columbia University and collaborators from Korea's Sungkyunkwan University and Japan's National Institute for Materials Science have reported that graphene can be efficiently doped using a monolayer of tungsten oxyselenide (TOS) that is created by oxidizing a monolayer of tungsten diselenide.

The new results relied on a cleaner technique to manipulate the flow of electricity, giving graphene greater conductivity than metals such as copper and gold, and raising its potential for use in telecommunications systems and quantum computers.

Read the full story Posted: Nov 02,2021

Princeton team gains better understanding of superconductivity in 'magic angle' graphene

Princeton researchers have dissipated some of the mystery around 'magic angle' graphene's superconductivity by showing an uncanny resemblance between it and the superconductivity of high temperature superconductors. Magic graphene may hold the key to unlocking new mechanisms of superconductivity, including high temperature superconductivity.

Ali Yazdani, Professor of Physics and Director of the Center for Complex Materials at Princeton University, led the research. He and his team have studied many different types of superconductors over the years and have recently turned their attention to magic bilayer graphene. Some have argued that magic bilayer graphene is actually an ordinary superconductor disguised in an extraordinary material, said Yazdani, but when we examined it microscopically it has many of the characteristics of high temperature cuprate superconductors. It is a déjà vu moment.

Read the full story Posted: Oct 21,2021