Kwon Duhyuk, Kim Bum-Kyu, Doh Yong-Joo, Yu Dong, Song Jonghyun, Bae Myung-Ho
Department of Physics, Chungnam National University, Daejeon 34134, Republic of Korea.
Korea Research Institute of Standards and Science, Daejeon34113, Republic of Korea.
iScience. 2023 Jan 5;26(1):105691. doi: 10.1016/j.isci.2022.105691. eCollection 2023 Jan 20.
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 BiSe) 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 = 15 K. We suggest that thermoelectric measurements could be applied for investigating the electronic structure at the Fermi level in various quantum materials.
拓扑绝缘体纳米线拓扑保护表面态中的子带磁通量相关色散表现为电导测量中观察到的阿哈罗诺夫 - 玻姆振荡（ABOs），这反映了由于自旋螺旋表面态导致的贝里相位π。在此，我们利用热电测量来探测拓扑绝缘体纳米线（Sb掺杂的BiSe）表面态费米能级处的态密度在外部磁场和施加的栅极电压下的变化。在磁热电压中观察到的ABOs根据栅极电压值呈现180°异相振荡，这可用于调节费米波数和费米能级处的态密度。ABO振幅的温度依赖性表明，相位相干在T = 15 K时仍得以保持。我们认为热电测量可用于研究各种量子材料费米能级处的电子结构。
