Fermi-level tuning of the Dirac surface state in (Bi1−xSbx)2Se3 thin films. (1st February 2018)

• Record Type: Journal Article
• Authors: Satake, Yosuke; Shiogai, Junichi; Takane, Daichi; Yamada, Keiko; Fujiwara, Kohei; Souma, Seigo; Sato, Takafumi; Takahashi, Takashi; Tsukazaki, Atsushi
• Is Part Of: Journal of physics. Volume 30:Number 8(2018)
• Publication Date: 2018-02-01
• Subjects: topological insulator -- molecular beam epitaxy -- bismuth selenide -- angle-resolved photoemission spectroscopy -- electrical transoport -- Dirac surface state; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aaa724
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: We report on the electronic states and the transport properties of three-dimensional topological insulator (Bi1− x Sb x )2 Se3 ternary alloy thin films grown on an isostructural Bi2 Se3 buffer layer on InP substrates. By angle-resolved photoemission spectroscopy, we clearly detected Dirac surface states with a large bulk band gap of 0.2–0.3 eV in the (Bi1− x Sb x )2 Se3 film with x = 0.70. In addition, we observed by Hall effect measurements that the dominant charge carrier converts from electron ( n -type) to hole ( p -type) at around x = 0.7, indicating that the Fermi level can be controlled across the Dirac point. Indeed, the carrier transport was shown to be governed by Dirac surface state in 0.63 ⩽ x ⩽ 0.75. These features suggest that Fermi-level tunable (Bi1− x Sb x )2 Se3 -based heterostructures provide a platform for extracting exotic topological phenomena.