Publication Date

1-11-2018

Department

Ames Laboratory; Physics and Astronomy; Materials Science and Engineering; Chemical and Biological Engineering

Campus Units

Chemical and Biological Engineering, Materials Science and Engineering, Physics and Astronomy, Ames Laboratory

OSTI ID+

1419932

Report Number

IS-J 9564

DOI

10.1021/acs.jpcc.7b11111

Journal Title

Journal of Physical Chemistry C

Volume Number

122

Issue Number

1

First Page

705

Last Page

713

Abstract

Topological quantum states require stringent combination of crystal symmetry and spin–orbit coupling (SOC) strength. Here, we report that the ternary Zintl compound series BaCaX (X = Si, Ge, Sn and Pb, Group IV) in the same crystal structure having eight valence electrons per formula unit can host two different topological quantum phases, controlled by atomic size and SOC strength. BaCaSi is a nodal-line semimetal (NLSM) with band inversion protected by mirror symmetry and hosts a strong topological insulator (TI) state when SOC is turned on, thus, a NLSM-TI phase. Moving to larger atomic sizes and heavier atoms, BaCaGe and BaCaSn are normal insulators (NIs); then, with the strongest SOC in BaCaPb, a different band inversion is induced, giving a strong TI phase without the need of NLSM. Thus, we also predict two types of topological transitions in a phase diagram for BaCaX: (1) NLSM-TI to NI, then to TI by tuning atomic size and SOC strength via alloying, and (2) NI or TI to NLSM-TI via pressure.

DOE Contract Number(s)

AC02-07CH11358

Language

en

Department of Energy Subject Categories

36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Publisher

Iowa State University Digital Repository, Ames IA (United States)

Available for download on Friday, December 14, 2018

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