Observation of topological order in a superconducting doped topological insulator
Observation of topological order in a superconducting doped topological insulator
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DOI：
10.1038/nphys1762
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发表时间：
2010-11
期刊：
影响因子：
19.6
通讯作者：
L. Wray;Su-Yang Xu;Yuqi Xia;D. Qian;A. Fedorov;Hsin Lin;A. Bansil;Y. Hor;R. Cava;M Zahid
中科院分区：
文献类型：
--
作者：
L. Wray;Su-Yang Xu;Yuqi Xia;D. Qian;A. Fedorov;Hsin Lin;A. Bansil;Y. Hor;R. Cava;M Zahid
最近，对三维块状固体中拓扑有序性的实验观察引发了一系列的研究活动，如，，，。与二维电子气或量子霍尔系统不同，三维拓扑绝缘体可以具有超导和磁性，这使得研究拓扑有序相和破缺对称态之间的相互作用成为可能。这种相互作用的一个结果是可能在拓扑面上实现Majorana费米子--作为它们自己的反粒子的准粒子--这是基础物理学中非常感兴趣的，，，。本文测量了铜掺杂Bi2Se_3的体电子动力学和表面电子动力学，并首次观察到了它的拓扑性质，其转变温度T_p为3.8 K。我们的数据表明，超导电性发生在块体相对论准粒子区域，其中不寻常的掺杂机制使得自旋极化的拓扑表面态在发生库珀配对的超导体的费米能级上保持完好。这些结果表明，超导Bi2Se_3中的电子动力学适合于捕获非阿贝尔马约拉纳费米子。我们观察到的细节构成了发展掺杂拓扑绝缘体中拓扑超导电性的一般理论的重要线索。
Experimental observation of topological order in three-dimensional bulk solids has recently led to a flurry of research activity,,,,,,,,,,,,,,,,,,,,. Unlike the two-dimensional electron gas or quantum Hall systems, three-dimensional topological insulators can harbour superconductivity and magnetism, making it possible to study the interplay between topologically ordered phases and broken-symmetry states. One outcome of this interplay is the possible realization of Majorana fermions—quasiparticles that are their own antiparticles—on topological surfaces, which is of great interest in fundamental physics,,,,,,,. Here we present measurements of the bulk and surface electron dynamics in Bi2Se3doped with copper with a transition temperatureTcup to 3.8 K, observing its topological character for the first time. Our data show that superconductivity occurs in a bulk relativistic quasiparticle regime where an unusual doping mechanism causes the spin-polarized topological surface states to remain well preserved at the Fermi level of the superconductor where Cooper pairing takes place. These results suggest that the electron dynamics in superconducting Bi2Se3are suitable for trapping non-Abelian Majorana fermions. Details of our observations constitute important clues for developing a general theory of topological superconductivity in doped topological insulators.