セガワ コウジ   SEGAWA KOJI
  瀬川 耕司
   所属   京都産業大学  理学部 物理科学科
   職種   教授
言語種別 英語
発行・発表の年月 2012/04
形態種別 研究論文
標題 Fermi level tuning and a large activation gap achieved in the topological insulator Bi2Te2Se by Sn doping
執筆形態 その他
掲載誌名 PHYSICAL REVIEW B
出版社・発行元 AMER PHYSICAL SOC
巻・号・頁 85(15)
著者・共著者 Zhi Ren,A. A. Taskin,Satoshi Sasaki,Kouji Segawa,Yoichi Ando
概要 We report the effect of Sn doping on the transport properties of the topological insulator Bi2Te2Se studied in a series of Bi2-xSnxTe2Se crystals with 0 <= x <= 0.02. The undoped stoichiometric compound (x = 0) shows an n-type metallic behavior with its Fermi level pinned to the conduction band. In the doped compound, it is found that Sn acts as an acceptor and leads to a downshift of the Fermi level. For x >= 0.004, the Fermi level is lowered into the bulk forbidden gap and the crystals present a resistivity considerably larger than 1 Omega cm at low temperatures. In those crystals, the high-temperature transport properties are essentially governed by thermally activated carriers whose activation energy is 95-125 meV, which probably signifies the formation of a Sn-related impurity band. In addition, the surface conductance directly obtained from the Shubnikov-de Haas oscillations indicates that a surface-dominated transport can be achieved in samples with several mu m thickness.
DOI 10.1103/PhysRevB.85.155301
ISSN 1098-0121
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