open access

https://hdl.handle.net/2115/66588

Stability of flat zero-energy states at the dirty surface of a nodal superconductor

英語

2017-06-05

American Physical Society (APS)

Physical Review B

95(21)

214503-1-214503-11

We discuss the stability of highly degenerate zero-energy states that appear at the surface of a nodal superconductor preserving time-reversal symmetry. The existence of such surface states is a direct consequence of the nontrivial topological numbers defined in the restricted Brillouin zones in the clean limit. In experiments, however, potential disorder is inevitable near the surface of a real superconductor, which may lift the high degeneracy at zero energy. We show that an index defined in terms of the chiral eigenvalues of the zero-energy states can be used to measure the degree of degeneracy at zero energy in the presence of potential disorder. We also discuss the relationship between the index and the topological numbers.

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©2017 American Physical Society

2469-9950