Topological phases and surface flat bands in superconductors without inversion symmetry

By A. Schnyder, S. Ryu. 2010

180 citations recorded by the source corpus.

We examine different topological phases in three-dimensional noncentrosymmetric superconductors with time-reversal symmetry by using three different types of topological invariants. Due to the bulk boundary correspondence, a nonzero value of any of these topological numbers indicates the appearance of zero-energy Andreev surface states. We find that some of these boundary modes in nodal superconducting phases are dispersionless, i.e., they form a topologically protected flat band. The region where the zero-energy flat band appears in the surface Brillouin zone is determined by the projection of the nodal lines in the bulk onto the surface. These dispersionless Andreev surface bound states have many observable consequences, in particular, a zero-bias conductance peak in tunneling measurements. We also find that in the gapless phase there appear Majorana surface modes at time-reversal invariant momenta which are protected by a ${\mathbb{Z}}_{2}$ topological invariant.

Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics

View Paper: https://www.semanticscholar.org/paper/839742d58e4eb2b99f6fc1a77afc19f0bce268a1

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In Atomic and Molecular Physics, and Optics

In Condensed Matter Physics

Citations in the corpus

Weyl and Dirac semimetals in three-dimensional solids (2017, background): “Other nodal superconductors can realize line nodes in the 3D BZ, and realize zero energy Andreev bound states at the surface BZ momenta that lie within the projections of these line nodes (Schnyder and Ryu, 2011).”
Topological superconductors: a review (2016, background): “The topological nature of 3D nodal noncentrosymmetric superconductors has been analyzed [80, 81, 85] and it was predicted that surface flat bands of topological origin should show up as a result of non-trivial bulk topology [60, 82].”
Symmetry and Topology in Non-Hermitian Physics (2018, methodology): “In similar to 1D class DIII for the Hermitian case [237–239], the Z2 invariant ν ∈ {0, 1} is thus given as”