p-type Bi₂ Se₃ for Topological Insulator and Low-Temperature Thermoelectric Applications

Author

Yew San Hor, Missouri University of Science and TechnologyFollow
Anthony R. Richardella
Pedram Roushan
Yuqi Xia
Joseph G. Checkelsky
Ali M. Yazdani
Md Zahid Hasan
Naiphuan Ong
Robert Joseph Cava

Abstract

The growth and elementary properties of p-type Bi₂Se₃ single crystals are reported. Based on a hypothesis about the defect chemistry of Bi₂Se₃, the p-type behavior has been induced through low-level substitutions (1% or less) of Ca for Bi. Scanning tunneling microscopy is employed to image the defects and establish their charge. Tunneling and angle-resolved photoemission spectra show that the Fermi level has been lowered into the valence band by about 400 meV in Bi_1.98Ca_0.02Se₃ relative to the n-type material. p-type single crystals with ab-plane Seebeck coefficients of +180 μV/K at room temperature are reported. These crystals show an anomalous peak in the Seebeck coefficient at low temperatures, reaching +120 μV K^-1 at 7 K, giving them a high thermoelectric power factor at low temperatures. In addition to its interesting thermoelectric properties, p-type Bi₂Se₃ is of substantial interest for studies of technologies and phenomena proposed for topological insulators.

Recommended Citation

Y. S. Hor et al., "p-type Bi₂ Se₃ for Topological Insulator and Low-Temperature Thermoelectric Applications," Physical review B: Condensed matter and materials physics, vol. 79, no. 19, American Physical Society (APS), May 2009.

The definitive version is available at https://doi.org/10.1103/PhysRevB.79.195208

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

© 2009 American Physical Society (APS), All rights reserved.

Publication Date

01 May 2009