Work

Filling-Enforced Gaplessness in Band Structures of the 230 Space Groups

Year: 2016

Type: article

Abstract: Nonsymmorphic symmetries like screws and glides produce electron band touchings, obstructing the formation of a band insulator and leading, instead, to metals or nodal semimetals even when the number of electrons in the unit cell is an even integer. Here, we calculate the electron fillings compatible with being a band insulator for all 230 space groups, for noninteracting electrons with time-reversal symmetry. Our bounds are tight-that is, we can rigorously eliminate band insulators at any forbidden filling and produce explicit models for all allowed fillings-and stronger than those recently established for interacting systems. These results provide simple criteria that should help guide the search for topological semimetals and, also, have implications for both the nature and stability of the resulting nodal Fermi surfaces.

Source: Physical Review Letters

DOI: 10.1103/physrevlett.117.096404

Authors: Haruki Watanabe, Hoi Chun Po, Michael P. Zaletel, Ashvin Vishwanath

Institutions: The University of Tokyo, University of California, Berkeley, Microsoft (United States), Lawrence Berkeley National Laboratory

Language: English

Topic: Topological Materials and Phenomena

Subfield: Condensed Matter Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, Massachusetts Institute of Technology, Division of Materials Research

Awards: G6364960172, CDS&E: Collaborative Research: Computational Design of Topological Superconductors and Weyl - Dirac Semimetals