Electronic states on a twin boundary of a d-wave superconductor

TL;DR

This paper investigates how an induced s-wave component in an orthorhombic d-wave superconductor influences the local electronic states near a twin boundary, revealing zero-energy bound states and unique scattering effects.

Contribution

It demonstrates the significant impact of an induced s-wave harmonic on the excitation spectrum and thermal transport properties at twin boundaries in d-wave superconductors.

Findings

Presence of zero-energy bound states proportional to s-wave component

Identification of a novel scattering process affecting thermal conductivity

Altered excitation spectrum near twin boundary

Abstract

We show that an induced $s$-wave harmonic in the superconducting gap of an orthorhombic $d_{x^2-y^2}$ superconductor strongly affects the excitation spectrum near a twinning plane. In particular, it yields bound states of zero energy with areal density proportional to the relative weight of the $s$-wave component. An unusual scattering process responsible for the thermal conductivity across the twin boundary at low temperatures is also identified.