Probing Majorana-like states in quantum dots and quantum rings
Probing Majorana-like states in quantum dots and quantum rings
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DOI：
10.1103/physrevb.91.144505
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发表时间：
2014-09
影响因子：
3.7
通讯作者：
B. Scharf;I. vZuti'c
中科院分区：
文献类型：
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作者：
B. Scharf;I. vZuti'c
半导体结构中的工程手性$p$波超导性提供了在凝聚态物质背景下获取和研究马约拉纳模式的有趣方法。在这里，我们从理论上研究了量子点和量子环中的手性$p$波超导性。使用分析和数值方法，我们计算了这些结构中的准粒子激发光谱以及相应的激发振幅和电荷密度。在拓扑结构中，我们可以观察到量子点和量子环中局域于边界且具有有限能量的手性边缘模式。通过施加从量子环中排出的磁场，但产生的通量是 $\Phi_0/2=\pi\hbar/e$ 的奇数倍，马约拉纳模式，即（近似）具有零能量和零电荷密度的简并边缘模式，在拓扑结构中成为可能。此外，我们研究了分裂这些简并边缘模式的有限尺寸效应，以及渗透到超导区域的磁场的影响，该区域在某些情况下仍然支持能量和电荷近似为零的边缘模式。
Engineering chiral $p$-wave superconductivity in semiconductor structures offers fascinating ways to obtain and study Majorana modes in a condensed matter context. Here, we theoretically investigate chiral $p$-wave superconductivity in quantum dots and quantum rings. Using both analytical as well as numerical methods, we calculate the quasiparticle excitation spectra in these structures and the corresponding excitation amplitudes and charge densities. In the topological regime, we can observe the chiral edge modes localized at the boundaries and possessing finite energy in quantum dots and quantum rings. By applying a magnetic field which is expelled from the quantum ring, but which creates a flux that is an odd integer multiple of $\Phi_0/2=\pi\hbar/e$, Majorana modes, that is, (approximately) degenerate edge modes with zero energy and zero charge density, become possible in the topological regime. Furthermore, we investigate finite-size effects that split these degenerate edge modes as well as the effect of a magnetic field penetrating into the superconducting region that can under certain circumstances still support edge modes with approximately zero energy and charge.