3D Dirac semimetals: current materials, design principles and predictions of new materials

TL;DR

This paper reviews current 3D Dirac semimetals, discusses design principles for new materials, and predicts several novel candidates based on different structural and electronic criteria.

Contribution

It introduces new design principles for 3D Dirac semimetals and predicts multiple novel candidate materials across various classes.

Findings

Current materials include TlBiSe$_{2-x}$S$_x$, Hg$_{1-x}$Cd$_x$Te, Bi$_{1-x}$Sb$_x$, Bi$_{2-x}$In$_x$Se$_3$, Pb$_{1-x}$Sn$_x$Se, Na$_3$Bi, and Cd$_3$As$_2$.

New candidates such as BaAgBi, SrAgBi, YbAuSb, PtBi$_2$, SrSn$_2$As$_2$, BaGa$_2$, BaPt, Li$_2$Pt, TlMo$_3$Te$_3$, and Cr$_2$B are predicted.

Abstract

Design principles and novel predictions of new 3D Dirac semimetals are presented, along with the context of currently known materials. Current materials include those based on a topological to trivial phase transition, such as in TlBiSe$_{2-x}$S$_x$ and Hg$_{1-x}$Cd$_x$Te, Bi$_{1-x}$Sb$_x$, Bi$_{2-x}$In$_x$Se$_3$, and Pb$_{1-x}$Sn$_x$Se. Some more recently revealed materials, Na$_3$Bi and Cd$_3$As$_2$, are 3D Dirac semimetals in their native composition. The different design principles presented each yield novel predictions for new candidates. For Case I, 3D Dirac semimetals based on charge balanced compounds, BaAgBi, SrAgBi, YbAuSb, PtBi$_2$ and SrSn$_2$As$_2$ are identified as candidates. For Case II, 3D Dirac semi-metals in analogy to graphene, BaGa$_2$ is identified as a candidate, and BaPt and Li$_2$Pt are discussed. For Case III, 3D Dirac semi-metals based on glide planes and screw axes, TlMo$_3$Te$_3$ and the AMo$_3$X$_3$ family in general (A=K, Na, In, Tl, X=Se,Te) as well as the Group IVb trihalides such as HfI$_3$ are identified as candidates. Finally we discuss conventional intermetallic compounds with Dirac cones, and identify Cr$_2$B as a potentially interesting material.