Direct observation of double valence-band extrema and anisotropic effective masses of the thermoelectric material SnSe. (8th December 2017)

• Record Type: Journal Article
• Authors: Nagayama, Takanobu; Terashima, Kensei; Wakita, Takanori; Fujiwara, Hirokazu; Fukura, Tetsushi; Yano, Yuko; Ono, Kanta; Kumigashira, Hiroshi; Ogiso, Osamu; Yamashita, Aichi; Takano, Yoshihiko; Mori, Hitoshi; Usui, Hidetomo; Ochi, Masayuki; Kuroki, Kazuhiko; Muraoka, Yuji; Yokoya, Takayoshi
• Is Part Of: Japanese journal of applied physics. Volume 57:Number 1(2018)
• Publication Date: 2017-12-08
• Subjects: Physics -- Periodicals; 621.05
• DOI: 10.7567/JJAP.57.010301
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: Synchrotron-based angle-resolved photoemission spectroscopy is used to determine the electronic structure of layered SnSe, which was recently turned out to be a potential thermoelectric material. We observe that the top of the valence band consists of two nearly independent hole bands, whose tops differ by ∼20 meV in energy, indicating the necessity of a multivalley model to describe the thermoelectric properties. The estimated effective masses are anisotropic, with in-plane values of 0.16–0.39 m 0 and an out-of-plane value of 0.71 m 0, where m 0 is the rest electron mass. Information of the electronic structure is essential to further enhance the thermoelectric performance of hole-doped SnSe.