Scanning tunneling microscopy (STM) is an indispensable tool in detecting Majorana bound states (MBSs) in vortices of topological superconductors. By reducing the computational complexity via non-uniform grids, we systematically study the tunnel coupling as well as the temperature dependence of the differential conductance of MBSs in two dimensional devices. Numerical results show that the conductance peak approaches the quantized value 2e 2/h in strong coupling limit at low temperatures which are characteristic features of MBSs. More interestingly, a conductance local minimum in the spatially scanning is observed when the STM tip is placed at the vortex center. The dip structure can be enhanced with increased temperature or enlarged vortex size. We ascribe this observation to the sensitivity of the Andreev reflection processes of carriers at the vortex center where the thermal energy could be comparable to the vanishing pair potential. We also investigate the STM of two-vortex systems where the hybridization of the vortices can lead to oscillatory behavior of the state energy. With small inter-vortex distances, the original MBSs in vortices can merge into topologically trivial states and the conductance peak can be significantly suppressed.

中文翻译：

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拓扑超导涡旋中马约拉纳束缚态扫描隧道显微镜的理论研究

扫描隧道显微镜 (STM) 是检测拓扑超导体涡旋中的马约拉纳束缚态 (MBS) 不可或缺的工具。通过非均匀网格降低计算复杂度，我们系统地研究了二维器件中 MBS 微分电导的隧道耦合和温度依赖性。数值结果表明，电导峰值在低温强耦合极限下接近量化值2e 2/h，这是MBSs的特征。更有趣的是，当 STM 尖端放置在涡旋中心时，在空间扫描中观察到电导局部最小值。可以通过增加温度或扩大涡流尺寸来增强倾斜结构。我们将此观察归因于涡旋中心载流子的安德列夫反射过程的敏感性，其中热能可与消失对势相媲美。我们还研究了双涡旋系统的 STM，其中涡旋的杂交会导致状态能量的振荡行为。由于涡旋间距离较小，涡旋中的原始 MBS 可以合并为拓扑微不足道的状态，并且可以显着抑制电导峰值。