Title

Development of Ferromagnetism in the Doped Topological Insulator Bi2-x MnxTe3

Abstract

The development of ferromagnetism in Mn-doped Bi2Te3 is characterized through measurements on a series of single crystals with different Mn content. Scanning tunneling microscopy analysis shows that the Mn substitutes on the Bi sites, forming compounds of the type Bi2-xMnxTe3, and that the Mn substitutions are randomly distributed, not clustered. Mn doping first gives rise to local magnetic moments with Curie-like behavior, but by the compositions Bi1.96 Mn0.04 Te3 and Bi1.91 Mn0.09 Te3, a second-order ferromagnetic transition is observed, with TC ~9-12 K. The easy axis of magnetization in the ferromagnetic phase is perpendicular to the Bi2 Te3 basal plane. Thermoelectric power and Hall effect measurements show that the Mn-doped Bi2Te3 crystals are p -type. Angle-resolved photoemission spectroscopy measurements show that the topological surface states that are present in pristine Bi2 Te3 are also present at 15 K in ferromagnetic Mn-doped Bi2-x MnxTe3 and that the dispersion relations of the surface states are changed in a subtle fashion.

Department(s)

Physics

International Standard Serial Number (ISSN)

1098-0121

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2010 American Physical Society (APS), All rights reserved.

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