Tunable double-Weyl Fermion semimetal state in the SrSi$_2$ materials class

Bahadur Singh; Guoqing Chang; Tay-Rong Chang; Shin-Ming Huang; Chenliang Su; Ming-Chieh Lin; Hsin Lin; Arun Bansil

doi:10.1038/s41598-018-28644-y

paper

Tunable double-Weyl Fermion semimetal state in the SrSi $_{2}$ materials class

arXiv:1807.05585 · doi:10.1038/s41598-018-28644-y

Abstract

We discuss first-principles topological electronic structure of noncentrosymmetric SrSi $_{2}$ materials class based on the hybrid exchange-correlation functional. Topological phase diagram of SrSi $_{2}$ is mapped out as a function of the lattice constant with focus on the semimetal order. A tunable double-Weyl Fermion state in Sr $_{1 - x}$ Ca $_{x}$ Si $_{2}$ and Sr $_{1 - x}$ Ba $_{x}$ Si $_{2}$ alloys is identified. Ca doping in SrSi $_{2}$ is shown to yield a double-Weyl semimetal with a large Fermi arc length, while Ba doping leads to a transition from the topological semimetal to a gapped insulator state. Our study indicates that SrSi $_{2}$ materials family could provide an interesting platform for accessing the unique topological properties of Weyl semimetals.

21 pages (Text file including 5 figures), Accepted in Nature Scientific Reports

Tunable double-Weyl Fermion semimetal state in the SrSi2​ materials class

Abstract

Tunable double-Weyl Fermion semimetal state in the SrSi $_{2}$ materials class