Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon, Korea.
Quantum Technology Institute, Korea Research Institute of Standards and Science, Daejeon, Korea.
Nat Commun. 2019 Oct 4;10(1):4522. doi: 10.1038/s41467-019-12560-4.
Aharonov-Bohm conductance oscillations emerge as a result of gapless surface states in topological insulator nanowires. This quantum interference accompanies a change in the number of transverse one-dimensional modes in transport, and the density of states of such nanowires is also expected to show Aharonov-Bohm oscillations. Here, we demonstrate a novel characterization of topological phase in BiSe nanowire via nanomechanical resonance measurements. The nanowire is configured as an electromechanical resonator such that its mechanical vibration is associated with its quantum capacitance. In this way, the number of one-dimensional transverse modes is reflected in the resonant frequency, thereby revealing Aharonov-Bohm oscillations. Simultaneous measurements of DC conductance and mechanical resonant frequency shifts show the expected oscillations, and our model based on the gapless Dirac fermion with impurity scattering explains the observed quantum oscillations successfully. Our results suggest that the nanomechanical technique would be applicable to a variety of Dirac materials.
无带隙表面态导致的反常霍尔电导振荡出现在拓扑绝缘体纳米线中。这种量子干涉伴随着输运中横向一维模式数量的变化，并且这种纳米线的态密度也有望表现出反常霍尔振荡。在这里，我们通过纳米力学共振测量证明了 BiSe 纳米线中拓扑相的一种新特性。该纳米线被配置为机电谐振器，使得其机械振动与量子电容相关联。通过这种方式，一维横向模式的数量反映在共振频率中，从而揭示了反常霍尔振荡。直流电导和机械共振频率变化的同时测量显示出了预期的振荡，我们基于具有杂质散射的无带隙狄拉克费米子的模型成功地解释了观察到的量子振荡。我们的结果表明，纳米力学技术将适用于各种狄拉克材料。
