Semiconductor–metal transition in Bi2Se3 caused by impurity doping

Takaki Uchiyama, Hidenori Goto, Eri Uesugi, Akihisa Takai, Lei Zhi, Akari Miura, Shino Hamao, Ritsuko Eguchi, Hiromi Ota, Kunihisa Sugimoto, Akihiko Fujiwara, Fumihiko Matsui, Koji Kimura, Kouichi Hayashi, Teppei Ueno, Kaya Kobayashi, Jun Akimitsu, Yoshihiro Kubozono

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4 Citations (Scopus)


Doping a typical topological insulator, Bi2Se3, with Ag impurity causes a semiconductor–metal (S-M) transition at 35 K. To deepen the understanding of this phenomenon, structural and transport properties of Ag-doped Bi2Se3 were studied. Single-crystal X-ray diffraction (SC-XRD) showed no structural transitions but slight shrinkage of the lattice, indicating no structural origin of the transition. To better understand electronic properties of Ag-doped Bi2Se3, extended analyses of Hall effect and electric-field effect were carried out. Hall effect measurements revealed that the reduction of resistance was accompanied by increases in not only carrier density but carrier mobility. The field-effect mobility is different for positive and negative gate voltages, indicating that the EF is located at around the bottom of the bulk conduction band (BCB) and that the carrier mobility in the bulk is larger than that at the bottom surface at all temperatures. The pinning of the EF at the BCB is found to be a key issue to induce the S-M transition, because the transition can be caused by depinning of the EF or the crossover between the bulk and the top surface transport.

Original languageEnglish
Article number537
JournalScientific reports
Issue number1
Publication statusPublished - Dec 2023

ASJC Scopus subject areas

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