Sub-gap in the Edge States of 2-D Chiral Superconductor with Rough Surface

Abstract

We discuss the rough surface effects on a two-dimensional chiral $k_x+i{k}_y$ superconductor. The atomic scale roughness at the surface is considered using the random $S$ matrix model. The roughness effects on the self-consistent order parameter, the surface mass current and the surface density of states are studied using the quasi-classical theory. We find that the surface mass current is suppressed by the surface roughness. The surface density of states shows a quite similar behavior to that of superfluid ${}^3$He B phase. When the surface is specular, the surface Andreev bound states form a band which fills the bulk energy gap ${\Delta }_{\mathrm{bulk}}$. When the surface becomes diffusive, there occurs a sharp upper edge of the surface bound states band and there opens a sub-gap between the edge and the bulk energy gap. We show that this sub-gap is induced by the repulsion between the surface bound states and the propagating Bogoliubov quasi-particles through the second order process of roughness.

To be oublished in J. Phys. Soc. Jpn

References in corpus (5)

• Classification of topological insulators and superconductors in three spatial dimensions
• Edge states of Sr${}_2$RuO${}_4$ detected by in-plane tunneling spectroscopy
• Thermodynamic properties of thin films of superfluid 3He-A
• Surface Majorana Cone of the Superfluid ${}^3$He B Phase
• Suppression of Spontaneous Supercurrents in a Chiral p-Wave Superconductor

Cited by in corpus (15)

• Symmetry Protected Topological Superfluids and Superconductors --- From the Basics to ${}^3$He ---
• Symmetry Protected Topological Superfluid ${}^3$He-B
• Edge Current due to Majorana Fermions in Superfluid ${}^3$He A- and B-Phases
• Anomalous surface states at interfaces in p-wave superconductors
• Spontaneous Edge Current in Higher Chirality Superconductors
• Destruction of surface states of ($d_{zx}+i{d}_{yz}$)-wave superconductor by surface roughness: application to Sr${}_2$RuO${}_4$
• Equilibrium Surface Current and Role of U(1) Symmetry: sum rule and surface perturbations
• Local impedance on a rough surface of a chiral $p$-wave superconductor
• Influence of diffuse surface scattering on the stability of superconducting phases with spontaneous surface current generated by Andreev bound states
• Non-thermodynamic nature of the orbital angular momentum in neutral fermionic superfluids
• Robustness of chiral surface current and subdominant $s$-wave Cooper pairs
• Intrinsic Angular Momentum and Intrinsic Magnetic Moment of Chiral Superconductor on Two-Dimensional Square Lattice
• Subgap in the surface bound states spectrum of Superfluid ${}^3$He-B with Rough Surface
• Fulde-Ferrell state in ferromagnetic chiral superconductor with magnetic domain wall
• Chiral Current Inversion Induced by Flat-Band Andreev Bound States