Spurred by recent progress in melting, enhancement and induction of electronic order out of equilibrium, a tantalizing prospect concerns instead accessing transient Floquet steady states via broad pump pulses, to affect electronic properties. Here, we consider a two-pronged approach to manipulate the topology of a band insulator, as well as topological order in a Mott insulator. We first develop a strategy to understand non-equilibrium Floquet-Bloch bands and topological transitions directly from ab initio calculations, and illustrate for the example of WS2 that control of chiral edge modes can be dictated solely from symmetry principles and is not qualitatively sensitive to microscopic materials details. Second, we extend these ideas to strongly correlated systems and show that pumping frustrated Mott insulators with circularly-polarized light can drive the effective spin system across a phase transition to a chiral spin liquid (CSL).The results presented suggest new avenues to marry dynamical symmetry breaking, strong interactions, and ab initio materials modelling, to access elusive phase transitions that are not readily accessible in equilibrium.

BIO: Professor Devereaux received his M.S. and Ph.D. in Physics from the University of Oregon in 1988 & 1991, respectively. He is the Director of the Stanford Institute for Materials and Energy Sciences (SIMES), the Associate Lab Director (ALD) for Photon Science, a professor in the Photon Science Faculty at SLAC National Accelerator Laboratory and Stanford University and a Senior Fellow of the Precourt Institute for Energy. His main research interests lie in the areas of theoretical condensed matter physics and computational physics. His research effort focuses on using the tools of computational physics to understand quantum materials. His group carries out numerical simulations on SIMES’ high-performance supercomputer, the National Energy Research Scientific Computing Center (NERSC), and other US and Canadian computational facilities.

Prof. Devereaux is being hosted by Prof. Gull (Physics). If you are interested in meeting him please send an email to mcteja@umich.edu.

For more information visit http://micde.umich.edu/event/micde-seminar-thomas-devereaux-photon-science-stanford-university/