Quantum Oscillations and Hall Anomaly of Surface States in the Topological Insulator Bi₂Te

Topological insulators are insulating materials that display massless, Dirac-like surface states in which the electrons have only one spin degree of freedom on each surface. These states have been imaged by photoemission, but little information on their transport parameters, for example, mobility, i...

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Bibliographic Details
Published inScience (American Association for the Advancement of Science) Vol. 329; no. 5993; pp. 821 - 824
Main Authors Qu, Dong-Xia, Hor, Y.S, Xiong, Jun, Cava, R.J, Ong, N.P
Format Journal Article
LanguageEnglish
Published American Association for the Advancement of Science 13.08.2010
Subjects
Conductivity
Crystals
Electric current
Electrical resistivity
Electrons
Hall effect
Magnetic fields
Mathematical surfaces
Photoelectric emission
Topology
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Summary:Topological insulators are insulating materials that display massless, Dirac-like surface states in which the electrons have only one spin degree of freedom on each surface. These states have been imaged by photoemission, but little information on their transport parameters, for example, mobility, is available. We report the observation of Shubnikov-de Haas oscillations arising from the surface states in nonmetallic crystals of Bi₂Te₃. In addition, we uncovered a Hall anomaly in weak fields, which enables the surface current to be seen directly. Both experiments yield a surface mobility (9000 to 10,000 centimeter² per volt-second) that is substantially higher than in the bulk. The Fermi velocity of 4 x 10⁵ meters per second obtained from these transport experiments agrees with angle-resolved photoemission experiments.
ISSN:0036-8075
1095-9203