Experimental Demonstration of Topological Surface States Protected by Time-Reversal Symmetry
Abstract
We report direct imaging of standing waves of the nontrivial surface states of topological insulator Bi2Te3 using a scanning tunneling microscope. The interference fringes are caused by the scattering of the topological states off Ag impurities and step edges on the Bi2Te3(111) surface. By studying the voltage-dependent standing wave patterns, we determine the energy dispersion E(k), which confirms the Dirac cone structure of the topological states. We further show that, very different from the conventional surface states, backscattering of the topological states by nonmagnetic impurities is completely suppressed. The absence of backscattering is a spectacular manifestation of the time-reversal symmetry, which offers a direct proof of the topological nature of the surface states.
- Publication:
-
Physical Review Letters
- Pub Date:
- December 2009
- DOI:
- 10.1103/PhysRevLett.103.266803
- arXiv:
- arXiv:0908.4136
- Bibcode:
- 2009PhRvL.103z6803Z
- Keywords:
-
- 73.20.-r;
- 68.37.Ef;
- 72.10.Fk;
- 72.25.Dc;
- Electron states at surfaces and interfaces;
- Scanning tunneling microscopy;
- Scattering by point defects dislocations surfaces and other imperfections;
- Spin polarized transport in semiconductors;
- Condensed Matter - Mesoscale and Nanoscale Physics
- E-Print:
- doi:10.1103/PhysRevLett.103.266803