Experimental Detection of a Majorana Mode in the core of a Magnetic Vortex inside a Topological Insulator-Superconductor Bi2Te3/NbSe2 Heterostructure
Experimental Detection of a Majorana Mode in the core of a Magnetic Vortex inside a Topological Insulator-Superconductor Bi2Te3/NbSe2 Heterostructure
复制标题
拓扑绝缘体-超导体 Bi2Te3/NbSe2 异质结构内磁涡旋核心马约拉纳模式的实验检测
DOI：
10.1103/physrevlett.114.017001
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发表时间：
2015-01-07
影响因子：
8.6
通讯作者：
Jia, Jin-Feng
中科院分区：
文献类型：
--
作者：
Xu, Jin-Peng;Wang, Mei-Xiao;Jia, Jin-Feng
近年来，Majorana费米子因其在基础科学和拓扑量子计算中的潜在应用而备受关注。它们被预测存在于超导拓扑绝缘子的涡核中。然而，由于Majorana费米子和这些状态之间的微小能量差异，从实验上将它们与其他准粒子状态区分开来是极其困难的，这超出了大多数现有技术的能量分辨率。在这里，我们通过系统地研究在超导体NbSe_2上生长的Bi2Te_3薄膜中的Majorana模和涡旋内束缚准粒子态的空间分布来绕过这个问题。虽然在常规超导体中，局域电导的零偏压峰正好从涡旋中心分裂出来，但它在距离Bi2Te3涡旋中心大约20 nm的有限距离处分裂。这种不同寻常的分裂行为以前从未被观察到过，可能是由于马约拉纳费米子零模。当马约拉纳模被涡旋之间的相互作用破坏时，零偏压峰再次像常规超导体那样分裂。这项工作提供了马约拉纳费米子的自洽证据，并提出了一种可能的操纵它们的途径。
Majorana fermions have been intensively studied in recent years for their importance to both fundamental science and potential applications in topological quantum computing. They are predicted to exist in a vortex core of superconducting topological insulators. However, it is extremely difficult to distinguish them experimentally from other quasiparticle states for the tiny energy difference between Majorana fermions and these states, which is beyond the energy resolution of most available techniques. Here, we circumvent the problem by systematically investigating the spatial profile of the Majorana mode and the bound quasiparticle states within a vortex in Bi2Te3 films grown on a superconductor NbSe2. While the zero bias peak in local conductance splits right off the vortex center in conventional superconductors, it splits off at a finite distance similar to 20 nm away from the vortex center in Bi2Te3. This unusual splitting behavior has never been observed before and could be possibly due to the Majorana fermion zero mode. While the Majorana mode is destroyed by the interaction between vortices, the zero bias peak splits as a conventional superconductor again. This work provides self-consistent evidences of Majorana fermions and also suggests a possible route to manipulating them.