Quantum Oscillations and Hall Anomaly of Surface States in the Topological Insulator Bi2Te3

• Published in: Science (American Association for the Advancement of Science) Vol. 329; no. 5993; pp. 821 - 824
• Main Authors: QU, Dong-Xia, HOR, Y. S, JUN XIONG, CAVA, R. J, ONG, N. P
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 13.08.2010; The American Association for the Advancement of Science
• Subjects: Anomalies; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Conductivity phenomena in semiconductors and insulators; Crystals; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in condensed matter; Electrons; Exact sciences and technology; Galvanomagnetic and other magnetotransport effects; Halls; Insulation; Insulators; Materials science; Mathematical analysis; Measuring instruments; Oscillations; Photoemission; Physics; Quantum physics; Semiconductor research; Surface and interface electron states; Surface states, band structure, electron density of states; Transport; Bismuth tellurides; Topological insulator; Degrees of freedom; Inorganic compounds; Surface electron state; Angle resolved photoemission spectroscopy; Anomaly; Hall effect; Quantum oscillation; Shubnikov-de Haas effect
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.1189792

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 Bi(2)Te(3). 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 centimeter(2) per volt-second) that is substantially higher than in the bulk. The Fermi velocity of 4 x 10(5) meters per second obtained from these transport experiments agrees with angle-resolved photoemission experiments.