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 Δ5, 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 Δ5|m|Δ5 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 Δ5 pairing can be extrinsically induced by a conventional s-wave superconductor into a three dimensional Dirac material (3DDM).
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机译:我们建议,自旋单伪标量S波超导配对在三维Dirac超导体(3DDS)的表面上创建二维的马洛纳费米子海。与标量狄拉克质量m竞争,该伪标量超导阶数参数Δ5由于能带反转而导致拓扑相变。我们发现,与传统的反常安德列夫反射一起存在,可以保证获得理想的安德烈耶夫-克莱因反射。这种效应在差分电导的共振峰中表现出来。此外,在存在异常安德列夫反射的情况下,Δ5| m |Δ5结的约瑟夫森电流在4π周期内为分数。我们的发现为马约拉那费米子的凝聚态实现提供了另一个搜索领域,该领域超出了p波超导体的涡旋核。所需的Δ5配对可以通过常规的s波超导体外生地引入三维Dirac材料(3DDM)中。
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