New Quasiparticle Discovered In Moiré Patterns

The Supersized Science podcast features research and discoveries nationwide enabled by advanced computing technology and expertise at the Texas Advanced Computing Center of the University of Texas at Austin. Jorge Salazar, a science writer at TACC, hosts the podcast. If you hold one wire mesh on top of another one and look through it, you'll see a larger pattern called a moiré pattern formed by the overlapping grids of the two meshes, which depends on their relative twisted angle. Scientists developing new materials are actively studying moiré patterns in overlapping atomically thin materials — they produce intriguing electronic phenomena that includes unconventional superconductivity and ferromagnetism. Supercomputer simulations have helped scientists reveal in a bilayer moiré system a new species of an electronic phenomenon called an exciton, which is an electrically neutral quasiparticle, yet one that can carry energy and consists of an electron and electron ‘hole' that can be created for example by light impinging certain semiconductors and other materials. The research was published August 2022 in the journal Nature. In it, the scientists developed computer models that go beyond the conventional parameterized models that have been used to describe moiré systems and moiré excitons. Instead, they performed ab initio calculations that only start with the identity and initial position of the 3,903 atoms of the moiré superlattice unit cell. On the podcast to talk about their study are Steven G. Louie, a distinguished professor of physics at the University of California, Berkeley, and a senior faculty scientist at the Lawrence Berkeley National Laboratory; Mit Naik, a postdoctoral researcher working with Professor Louie at UC Berkeley and LBNL; and Felipe Jornada, Assistant Professor in the Department of Materials Science and Engineering at Stanford University and a Principal Investigator at the SLAC National Accelerator Laboratory. Supersized Science is part of the Texas Podcast Network – the conversations changing the world – brought to you by The University of Texas at Austin. The opinions expressed in this podcast represent the views of the hosts, and not of The University of Texas at Austin. Story Link: www.tacc.utexas.edu/-/new-quasipart…-moire-patterns Music Credit: Raro Bueno, Chuzausen freemusicarchive.org/music/Chuzausen/