In the quantum theory of solids, a metal is distinguished from an insulator by having a Fermi surface - a surface (in momentum space) where "the drama of the life of the electron is played out", leading to all properties unique to metals, e.g., their lustrous appearance, and their ability to conduct heat and electricity. Traditionally, solid-state physicists have focused on experimentally determining the shape of the Fermi surface. Today, emphasis has shifted to determining the quantum geometry of electronic wave functions on the Fermi surface – an electron travelling around the Fermi surface acquires a geometric Berry phase. For some symmetry classes of metals, such Berry phase is nontrivial and unchanging under perturbations of the metal. Such robustness is the hallmark of a new generation of ‘topological metals’, whose recent discovery has revolutionized the field of condensed matter with the promise of new functionalities. As a first step toward such functionalities, material candidates must be grown in laboratories and experimentally verified to be truly topological. For this purpose, I will describe how a time-honored experimental technique (magnetic quantum oscillations) can be refined to unambiguously distinguish a topological metal from a conventional one.
The Zoom link will be sent to the Graduate Student and PDRA mailing lists. If you are not on one of those lists and are interested in attending, please email Mark Hirsbrunner at hrsbrnn2@illinois.edu for the link.
