Fragile surface zero-energy flat bands in three-dimensional chiral superconductors
Fragile surface zero-energy flat bands in three-dimensional chiral superconductors
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DOI：
10.1103/physrevb.92.214514
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发表时间：
2015-12-28
影响因子：
3.7
通讯作者：
Sato, Masatoshi
中科院分区：
文献类型：
--
作者：
Kobayashi, Shingo;Tanaka, Yukio;Sato, Masatoshi
我们基于拓扑参数和隧道电导，研究具有 p(z) (p(x) + ip(y))(nu) 波配对对称性（nu 是非零整数）的三维手性超导体中的表面零能量平带。结果表明，表面平带对于 (i) 表面取向错误和 (ii) 表面 Rashba 自旋轨道相互作用很脆弱。 (i) 的脆弱性是手性 SC 特有的，而 (ii) 的脆弱性则发生在一般奇宇称 SC 中。我们证明这些平带不稳定性消失或抑制了正常/绝缘体/超导体结中的零偏置电导峰值，这种行为明显不同于高 T-c 铜酸盐和非中心对称超导体。通过计算角度分辨电导，我们还讨论了与线和点节点共存相关的拓扑表面状态。
We study surface zero-energy flat bands in three-dimensional chiral superconductors with p(z) (p(x) + ip(y))(nu)-wave pairing symmetry (nu is a nonzero integer), based on topological arguments and tunneling conductance. It is shown that the surface flat bands are fragile against (i) the surface misorientation and (ii) the surface Rashba spin-orbit interaction. The fragility of (i) is specific to chiral SCs, whereas that of (ii) happens for general odd-parity SCs. We demonstrate that these flat-band instabilities vanish or suppress a zero-bias conductance peak in a normal/insulator/superconductor junction, which behavior is clearly different from high-T-c cuprates and noncentrosymmetric superconductors. By calculating the angle-resolved conductance, we also discuss a topological surface state associated with the coexistence of line and point nodes.