Title: Topological semimetal to insulator quantum phase transition in the Zintl compounds $\mathrm{B}{\mathrm{a}}_{2}X(X=\mathrm{Si},\mathrm{Ge})$

Abstract

By first-principles calculations, we find that Ba₂X (X = Si, Ge) hosts a topological semimetal phase with one nodal ring in the k_x = 0 plane, which is protected by the glide mirror symmetry when spin-orbit coupling (SOC) is ignored. The corresponding drumheadlike surface flat band appears on the (100) surface in surface Green's function calculation. Furthermore, a topological-semimetal-to-insulator transition is found. The nodal line semimetal would evolve into a topological insulator as SOC is turned on. The topologically protected metallic surface states emerge around the Γ point, which could be tuned into the topologically trivial insulator state by more than 3% hydrostatic strain. These results reveal a category of materials showing quantum phase transition between topological semimetal and insulator, and tunability through elastic strain engineering.

Authors:

Zhu, Ziming ^[1]; Li, Mingda ^[2]; Li, Ju ^[1]

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+ Show Author Affiliations

1. Xi'an Jiaotong Univ., Xi'an (China). Frontier Inst. of Science and Technology, and State Key Lab. for Mechanical Behavior of Materials; Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Nuclear Science and Engineering and Dept. of Materials Science and Engineering
2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Mechanical Engineering

Publication Date:

Thu Oct 13 00:00:00 EDT 2016

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Solid-State Solar-Thermal Energy Conversion Center (S3TEC); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1388449

Alternate Identifier(s):

OSTI ID: 1328824

Grant/Contract Number:  

SC0001299; FG02-09ER46577

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review B

Additional Journal Information:

Journal Volume: 94; Journal Issue: 15; Related Information: S3TEC partners with Massachusetts Institute of Technology (lead); Boston College; Oak Ridge National Laboratory; Rensselaer Polytechnic Institute; Journal ID: ISSN 2469-9950

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY