Topological nodal-line semimetals in alkaline-earth stannides, germanides, and silicides

Huaqing Huang, Jianpeng Liu, David Vanderbilt, Wenhui Duan

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160 Scopus citations

Abstract

Based on first-principles calculations and an effective Hamiltonian analysis, we systematically investigate the electronic and topological properties of alkaline-earth compounds AX2 (A=Ca, Sr, Ba; X=Si, Ge, Sn). Taking BaSn2 as an example, we find that when spin-orbit coupling is ignored, these materials are three-dimensional topological nodal-line semimetals characterized by a snakelike nodal loop in three-dimensional momentum space. Drumheadlike surface states emerge either inside or outside the loop circle on the (001) surface depending on surface termination, while complicated double-drumhead-like surface states appear on the (010) surface. When spin-orbit coupling is included, the nodal line is gapped and the system becomes a topological insulator with Z2 topological invariants (1;001). Since spin-orbit coupling effects are weak in light elements, the nodal-line semimetal phase is expected to be achievable in some alkaline-earth germanides and silicides.

Original languageEnglish (US)
Article number201114
JournalPhysical Review B
Volume93
Issue number20
DOIs
StatePublished - May 26 2016

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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