85th CEMS Colloquium


Prof. Shuichi Murakami (Tokyo Institute of Technology)


17:30 - 18:30, October 21, 2020 (Wednesday)


Okochi-Hall, RIKEN


Theoretical approaches to topological materials


Topological materials have been attracting much interest in condensed matter physics. To date, thousands of materials have been identified to be topological by combining theories on topological materials with materials databases. Meanwhile, apart from such automated searches, we need deeper understanding on their topological nature. In my presentation, we explain a series of our works to understand their origins from various theoretical viewpoints. For example, studies on topological-nontopological phase transitions have shown us classes of topological materials called topological semimetals, which have been established among the family of topological materials. One can also have physical insight towards topological materials from the nature and structure of chemical bonding in crystals. For example, we propose that electrides, in which electrons serve as anions, are good candidates for topological materials. Recently we also study higher-order topological insulators, in which boundary gapless states appear at corners and hinges of the crystals. We show that in higher-order topological insulators, the dependence of the hinge states/corner states on crystal shapes show new features unique to higher-order topological insulators.