这篇博客报道了首次观察到在Bi2Te3/NbSe2异质结构中，Majorana费米子引起的磁性自旋选择性安德烈反射现象。利用扫描隧道显微镜/谱学技术，我们发现当磁极化方向与外磁场平行时， vortex中心的零偏压峰显著高于反平行情况。这直接证据了Majorana费米子的存在，并支持理论预测。研究为理解其新颖物理性质提供了决定性证据，推动了量子计算领域的研究。
摘要：
Majorana fermion (MF) whose antiparticle is itself has been predicted in condensed matter systems. Signatures of the MFs have been reported as zero energy modes in various systems. More definitive evidences are highly desired to verify the existence of the MF. Very recently, theory has predicted MFs to induce spin selective Andreev reflection (SSAR), a novel magnetic property which can be used to detect the MFs. Here we report the first observation of the SSAR from MFs inside vortices in Bi2Te3/NbSe2 hetero-structure, in which topological superconductivity was previously established. By using spin-polarized scanning tunneling microscopy/spectroscopy (STM/STS), we show that the zero-bias peak of the tunneling differential conductance at the vortex center is substantially higher when the tip polarization and the external magnetic field are parallel than anti-parallel to each other. Such strong spin dependence of the tunneling is absent away from the vortex center, or in a conventional superconductor. The observed spin dependent tunneling effect is a direct evidence for the SSAR from MFs, fully consistent with theoretical analyses. Our work provides definitive evidences of MFs and will stimulate the MFs research on their novel physical properties, hence a step towards their statistics and application in quantum computing.
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