Abstract
To explain the unusual nonsaturating linear magnetoresistance observed in silver chalcogenides, the quantum scenario has been proposed based on the assumption of gapless linear energy spectrum. Here we show, by first principles calculations, that with distorted antifluorite structure is in fact a topological insulator with gapless Dirac-type surface states. The characteristic feature of this new binary topological insulator is the highly anisotropic Dirac cone, in contrast with known examples, such as and . The Fermi velocity varies an order of magnitude by rotating the crystal axis.
- Received 6 January 2011
DOI:https://doi.org/10.1103/PhysRevLett.106.156808
© 2011 American Physical Society