论文标题

Majoraana versus Andreev绑定的状态能量振荡在一维半导体 - 驱动器异质结构中

Majorana versus Andreev bound state energy oscillations in a 1D semiconductor-superconductor heterostructure

论文作者

Sharma, Gargee, Zeng, Chuanchang, Stanescu, Tudor D., Tewari, Sumanta

论文摘要

在半导体 - 渗透导体主要纳米线中衰减的能量振荡的最新实验观察与基于在系统末端的Majorana零模式存在的典型期望与典型的期望形成了鲜明的对比,而杂交能量振动的幅度预计与施加的磁场相比会增加。这些观察结果在理论上是通过考虑位置依赖的,阶梯状的旋转轨道耦合的纳米线端的合理性的,这可能是由于标准隧道电导实验中存在隧道门而引起的。在这里,我们表明,与参数区域相比,该现象学发生的参数空间中的窗口消失了很小,在该参数区域中,Majorana振荡随施加场的振幅增加。此外,包括依赖位置的有效电位,例如,该电位也自然地通过隧道门在电线末端附近引起,实际上会删除与衰减振荡相关的小窗口。使用广泛的数值计算,我们表明,正如预期的那样,增加杂交能量的振幅振荡代表了拓扑主体零模式的通用特性,而降低振幅振荡是低能量琐碎的Andreev结合状态的通用性能,通常在非均匀系统中通常出现。通过平均几种逼真的参数配置,我们确定了杂交能的鲁棒特征,可以在典型的微分电导实验中观察到,而无需微调控制参数。

The recent experimental observations of decaying energy oscillations in semiconductor-superconductor Majorana nanowires is in contrast with the typical expectations based on the presence of Majorana zero modes localized at the ends of the system, when the amplitude of the hybridization energy oscillations is predicted to increase with the applied magnetic field. These observations have been theoretically justified recently by considering a position-dependent, step-like spin-orbit coupling near end of the nanowire, which could arise due to the presence of tunnel gates in a standard tunneling conductance experiment. Here, we show that the window in parameter space where this phenomenology occurs is vanishingly small, when compared to the parameter region where Majorana oscillations increase in amplitude with the applied field. Further, including a position-dependent effective potential, which is also induced naturally near the end of the wire by, e.g., tunnel gates, practically removes the small window associated with decaying oscillations. Using extensive numerical calculations, we show that, as expected, increasing amplitude oscillations of the hybridization energy represent a generic property of topological Majorana zero modes, while decreasing amplitude oscillations are a generic property of low-energy trivial Andreev bound states that typically emerge in non-homogeneous systems. By averaging over several realistic parameter configurations, we identify robust features of the hybridization energy that can be observed in a typical differential conductance experiment without fine-tuning the control parameters.

扫码加入交流群

加入微信交流群

微信交流群二维码

扫码加入学术交流群,获取更多资源