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Title: Different Topological Quantum States in Ternary Zintl compounds: BaCaX (X = Si, Ge, Sn and Pb)

Topological quantum states require stringent combination of crystal symmetry and spin–orbit coupling (SOC) strength. Here in this paper, 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.
Authors:
ORCiD logo [1] ;  [2] ;  [2] ; ORCiD logo [3]
  1. Ames Lab., Ames, IA (United States)
  2. Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy
  3. Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy; Iowa State Univ., Ames, IA (United States). Dept. of Materials Science & Engineering
Publication Date:
Report Number(s):
IS-J-9564
Journal ID: ISSN 1932-7447; TRN: US1801409
Grant/Contract Number:
AC02-07CH11358
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 122; Journal Issue: 1; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 36 MATERIALS SCIENCE
OSTI Identifier:
1419932

Wang, Lin-Lin, Kaminski, Adam, Canfield, Paul C., and Johnson, Duane D.. Different Topological Quantum States in Ternary Zintl compounds: BaCaX (X = Si, Ge, Sn and Pb). United States: N. p., Web. doi:10.1021/acs.jpcc.7b11111.
Wang, Lin-Lin, Kaminski, Adam, Canfield, Paul C., & Johnson, Duane D.. Different Topological Quantum States in Ternary Zintl compounds: BaCaX (X = Si, Ge, Sn and Pb). United States. doi:10.1021/acs.jpcc.7b11111.
Wang, Lin-Lin, Kaminski, Adam, Canfield, Paul C., and Johnson, Duane D.. 2017. "Different Topological Quantum States in Ternary Zintl compounds: BaCaX (X = Si, Ge, Sn and Pb)". United States. doi:10.1021/acs.jpcc.7b11111. https://www.osti.gov/servlets/purl/1419932.
@article{osti_1419932,
title = {Different Topological Quantum States in Ternary Zintl compounds: BaCaX (X = Si, Ge, Sn and Pb)},
author = {Wang, Lin-Lin and Kaminski, Adam and Canfield, Paul C. and Johnson, Duane D.},
abstractNote = {Topological quantum states require stringent combination of crystal symmetry and spin–orbit coupling (SOC) strength. Here in this paper, 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.},
doi = {10.1021/acs.jpcc.7b11111},
journal = {Journal of Physical Chemistry. C},
number = 1,
volume = 122,
place = {United States},
year = {2017},
month = {12}
}