Researchers point to moiré nematic phase in twisted double bilayer graphene

Researchers from Columbia University, Harvard University, RWTH Aachen University, University of Innsbruck, Drexel University, National Institute for Materials Science in Japan, University of Minnesota and others have studied twisted double sheets of bilayer graphene and have found an electronic nematic phase.

Moiré nematic phase in twisted double bilayer graphene image

First described in another state of matter called a liquid crystal, a nematic phase occurs when particles in a material break an otherwise symmetrical structure and come to loosely orient with one another along the same axis. This phenomenon is the basis of the LCD display commonly used in televisions and computer monitors. In an electronic nematic phase, the particles in question are electrons, whose behavior and arrangement in a material can influence how well that material will conduct an electrical current in different directions.

Researchers stabilize the edges of graphene nanoribbons and measure their magnetic properties

Researchers at Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley have developed a method to stabilize the edges of graphene nanoribbons and directly measure their unique magnetic properties.

The team, co-led by Felix Fischer and Steven Louie from Berkeley Lab’s Materials Sciences Division, found that by substituting some of the carbon atoms along the ribbon’s zigzag edges with nitrogen atoms, they could discretely tune the local electronic structure without disrupting the magnetic properties. This subtle structural change further enabled the development of a scanning probe microscopy technique for measuring the material’s local magnetism at the atomic scale.

New graphene-based neural probes improve detection of epileptic brain signals

Researchers the UK and Spain have demonstrated that tiny graphene neural probes can be used safely to improve our understanding of the causes of epilepsy.

The graphene depth neural probe (gDNP) consists of a millimeter-long linear array of micro-transistors imbedded in a micrometer-thin polymeric flexible substrate. The transistors were developed by a collaboration between The University of Manchester’s Neuromedicine Lab and UCL’s Institute of Neurology along with their Graphene Flagship partners.

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."

Researchers achieve precision sieving of gases through atomic pores in graphene

A team of researchers, led by Professor Sir Andre Geim at The University of Manchester, in collaboration with scientists from Belgium and China, used low-energy electrons to make individual atomic-scale holes in suspended graphene. The holes came in sizes down to about two angstroms, smaller than even the smallest atoms like helium and hydrogen.

Exponentially selective molecular sieving through angstrom pores image

The researchers report that they achieved practically perfect selectivity (better than 99.9%) for such gases as helium or hydrogen with respect to nitrogen, methane or xenon. Also, air molecules (oxygen and nitrogen) pass through the pores easily relative to carbon dioxide, which is >95% captured.