Science 2009-07-10

Experimental realization of a three-dimensional topological insulator, Bi2Te3.

Y L Chen, J G Analytis, J-H Chu, Z K Liu, S-K Mo, X L Qi, H J Zhang, D H Lu, X Dai, Z Fang, S C Zhang, I R Fisher, Z Hussain, Z-X Shen

Index: Science 325 , 178, (2009)

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Abstract

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 promising potential for high-temperature spintronics applications.