Submitted on March 4, 2009
Accepted on June 3, 2009
Experimental Realization of a Three-Dimensional Topological Insulator, Bi2Te3
Y. L. Chen 1, J. G. Analytis 2, J. H. Chu 2, Z. K. Liu 2, S.-K. Mo 3, X. L. Qi 2, H. J. Zhang 4, D. H. Lu 5, X. Dai 4, Z. Fang 4, S. C. Zhang 2, I. R. Fisher 2, Z. Hussain 6, Z.-X. Shen 2*
1 Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.; Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, CA 94305, USA.; Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
2 Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.; Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, CA 94305, USA.
3 Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, CA 94305, USA.; Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
4 Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
5 Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
6 Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
* To whom correspondence should be addressed.
Z.-X. Shen , E-mail: zxshen{at}stanford.edu
Three-dimensional topological insulators are a new state of quantum matter with a bulk gap and odd number of relativistic Dirac fermions on the surface. By investigating the surface state of Bi2Te3 with angle resolved photoemission spectroscopy, we demonstrate that the surface state consists of a single nondegenerate Dirac cone. Furthermore, with appropriate hole-doping, the Fermi level can be tuned to intersect only the surface states, indicating a full energy gap for the bulk states. Our results establish that Bi2Te3 is a simple model system for the three-dimensional topological insulator with a single Dirac cone on the surface. The large bulk gap of Bi2Te3 also points to great potential for possible high-temperature spintronics applications.
