We report an experimental study of one-dimensional (1D) electronic transportin an InSb semiconducting nanowire. Three bottom gates are used to locallydeplete the nanowire creating a ballistic quantum point contact with only a fewconducting channels. In a magnetic field, the Zeeman splitting of thecorresponding 1D subbands is revealed by the emergence of conductance plateausat multiples of $e^2$/h, yet we find a quantized conductance pattern largelydependent on the configuration of voltages applied to the bottom gates. Inparticular, we can make the first plateau disappear leaving a first conductancestep of 2$e^2/h$, which is indicative of a remarkable two-fold subbanddegeneracy that can persist up to several Tesla. We conclude that the subbandenergy spacings and g-factors are strongly affected by the tunable landscape ofthe local electrostatic potential. Finally, our measurements reveal thepresence of discrete resonant states that, for certain gate voltage settings,produce conductance features resembling those expected from the opening of ahelical gap in the subband structure.
展开▼
机译：我们报告了InSb半导体纳米线中的一维（1D）电子传输的实验研究。三个底栅用于局部耗尽纳米线，从而仅与几个导电通道形成弹道量子点接触。在磁场中，电导平稳段$ e ^ 2 $ / h的倍数的出现揭示了相应的1D子带的塞曼分裂，但我们发现量化的电导模式主要取决于施加到底栅的电压的配置。尤其是，我们可以使第一个平台消失，并留下第一个电导阶跃2 $ e ^ 2 / h $，这表明了显着的两倍亚带简并可以持续到几个特斯拉。我们得出的结论是，子带能量间距和g因子受局部静电势的可调节态势强烈影响。最后，我们的测量结果揭示了离散谐振状态的存在，对于某些栅极电压设置，该谐振状态产生的电导特性类似于子带结构中螺旋间隙的开口所期望的电导特性。
展开▼
