Quantum interference probed by the thermovoltage in Sb-doped Bi2Se3 nanowires

Duhyuk Kwon; Bum-Kyu Kim; Yong-Joo Doh; Dong Yu; Jonghyun Song; Myung-Ho Bae

doi:10.1016/j.isci.2022.105691

Quantum interference probed by the thermovoltage in Sb-doped Bi₂Se₃ nanowires

iScience. 2023 Jan 5;26(1):105691. doi: 10.1016/j.isci.2022.105691. eCollection 2023 Jan 20.

Authors

Duhyuk Kwon^{1

2}, Bum-Kyu Kim², Yong-Joo Doh³, Dong Yu⁴, Jonghyun Song^{1

5}, Myung-Ho Bae^{2

6}

Affiliations

¹ Department of Physics, Chungnam National University, Daejeon 34134, Republic of Korea.
² Korea Research Institute of Standards and Science, Daejeon34113, Republic of Korea.
³ Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju61005, Korea.
⁴ Department of Physics, University of California at Davis, Davis, CA95616, USA.
⁵ Institute of Quantum Systems (IQS), Chungnam National University, Daejeon34134, Republic of Korea.
⁶ Department of Nano Science, University of Science and Technology, Daejeon, 34113, Republic of Korea.

Abstract

The magnetic-flux-dependent dispersions of sub-bands in topologically protected surface states of a topological insulator nanowire manifest as Aharonov-Bohm oscillations (ABOs) observed in conductance measurements, reflecting the Berry's phase of π because of the spin-helical surface states. Here, we used thermoelectric measurements to probe a variation in the density of states at the Fermi level of the surface state of a topological insulator nanowire (Sb-doped Bi₂Se₃) under external magnetic fields and an applied gate voltage. The ABOs observed in the magnetothermovoltage showed 180° out-of-phase oscillations depending on the gate voltage values, which can be used to tune the Fermi wave number and the density of states at the Fermi level. The temperature dependence of the ABO amplitudes showed that the phase coherence was kept to T = 15 K. We suggest that thermoelectric measurements could be applied for investigating the electronic structure at the Fermi level in various quantum materials.

Keywords: Energy materials; Quantum solids; Thermal property.