Salehi Morteza, Jafari S A
Department of Physics, Sharif University of Technology, Tehran, 11155-9161, Iran.
Theoretische Physik, Universität Duisburg-Essen, 47048, Duisburg, Germany.
Sci Rep. 2017 Aug 15;7(1):8221. doi: 10.1038/s41598-017-07298-2.
We suggest that spin-singlet pseudo-scalar s-wave superconducting pairing creates a two dimensional sea of Majorana fermions on the surface of three dimensional Dirac superconductors (3DDS). This pseudo-scalar superconducting order parameter Δ, in competition with scalar Dirac mass m, leads to a topological phase transition due to band inversion. We find that a perfect Andreev-Klein reflection is guaranteed by presence of anomalous Andreev reflection along with the conventional one. This effect manifests itself in a resonant peak of the differential conductance. Furthermore, Josephson current of the Δ|m|Δ junction in the presence of anomalous Andreev reflection is fractional with 4π period. Our finding suggests another search area for condensed matter realization of Majorana fermions which are beyond the vortex-core of p-wave superconductors. The required Δ pairing can be extrinsically induced by a conventional s-wave superconductor into a three dimensional Dirac material (3DDM).
我们认为，自旋单重态赝标量s波超导配对在三维狄拉克超导体（3DDS）表面产生了二维马约拉纳费米子海。这种赝标量超导序参量Δ与标量狄拉克质量m相互竞争，由于能带反转导致拓扑相变。我们发现，反常安德列夫反射与传统安德列夫反射的存在保证了完美的安德列夫 - 克莱因反射。这种效应表现为微分电导的共振峰。此外，在存在反常安德列夫反射的情况下，Δ|m|Δ结的约瑟夫森电流具有4π周期的分数特性。我们的发现为凝聚态物质中实现超越p波超导体涡旋核的马约拉纳费米子指出了另一个探索领域。所需的Δ配对可以由传统s波超导体外在地诱导到三维狄拉克材料（3DDM）中。
