Abstract
Based on the first-principles calculations, we reveal that TlN, a simple binary compound with wurtzite structure, is a three-dimensional (3D) topological insulator (TI) with effectively negative spin-orbit coupling , which makes it distinguished from other TIs by showing opposite spin-momentum locking effect in its surface states. The sign of depends on the hybridization between N- and Tl- states, and can be tuned from negative to positive by lattice strain or chemical substitution, which drives the system into a Dirac semimetal with 3D Dirac cones in its bulk states. Such topological phase transition can be realized by electronic mechanism without breaking any crystal symmetry.
2 More- Received 19 September 2014
- Revised 15 December 2014
DOI:https://doi.org/10.1103/PhysRevB.90.245308
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