Fermi level tuning of Ag-doped Bi 2 Se 3 topological insulator

• Published in: Scientific reports Vol. 9; no. 1; p. 5376
• Main Authors: Uesugi, Eri, Uchiyama, Takaki, Goto, Hidenori, Ota, Hiromi, Ueno, Teppei, Fujiwara, Hirokazu, Terashima, Kensei, Yokoya, Takayoshi, Matsui, Fumihiko, Akimitsu, Jun, Kobayashi, Kaya, Kubozono, Yoshihiro
• Format: Journal Article
• Language: English
• Published: England 01.12.2019
• ISSN: 2045-2322
• DOI: 10.1038/s41598-019-41906-7

The temperature dependence of the resistivity (ρ) of Ag-doped Bi Se (Ag Bi Se ) shows insulating behavior above 35 K, but below 35 K, ρ suddenly decreases with decreasing temperature, in contrast to the metallic behavior for non-doped Bi Se at 1.5-300 K. This significant change in transport properties from metallic behavior clearly shows that the Ag doping of Bi Se can effectively tune the Fermi level downward. The Hall effect measurement shows that carrier is still electron in Ag Bi Se and the electron density changes with temperature to reasonably explain the transport properties. Furthermore, the positive gating of Ag Bi Se provides metallic behavior that is similar to that of non-doped Bi Se , indicating a successful upward tuning of the Fermi level.