Abstract
A single two-dimensinoal Dirac fermion state has been recently observed on the surface of the topological insulator by angle-resolved photoemission spectroscopy. We study the surface band structure using theory and find an unconventional hexagonal warping term, which is the counterpart of cubic Dresselhaus spin-orbit coupling in rhombohedral structures. We show that this hexagonal warping term naturally explains the observed hexagonal snowflake Fermi surface. The strength of hexagonal warping is characterized by a single parameter, which is extracted from the size of the Fermi surface. We predict a number of testable signatures of hexagonal warping in spectroscopy experiments on . We also explore the possibility of a spin-density wave due to strong nesting of the Fermi surface.
- Received 12 August 2009
DOI:https://doi.org/10.1103/PhysRevLett.103.266801
©2009 American Physical Society
Viewpoint
Warping the cone on a Topological Insulator
Published 21 December 2009
The energy-momentum relationship of electrons on the surface of an ideal topological insulator forms a cone, which, when warped, can lead to unusual phenomena such as enhanced interference around defects and a magnetically ordered exotic surface.
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