Quasiparticle spectrum of grain boundaries in d-wave superconductors

TL;DR

This paper investigates the quasiparticle spectrum at grain boundaries in d-wave superconductors, revealing how misorientation affects localized states and density of states, with implications for understanding superconducting grain boundary properties.

Contribution

It provides a detailed analysis of the quasiparticle spectrum at grain boundaries with varying misorientation angles in d-wave superconductors, highlighting the emergence of zero energy states.

Findings

Density of states is enhanced at low energies.

Number of localized states depends on misfit angle.

Zero energy states appear at specific rotation angles.

Abstract

A grain boundary which separates domains with different orientation along the c-axis is analyzed. The coupling of two parallel superconducting planes whose order parameters are rotated leads to interesting properties which are expected to be common to other kinds of grain boundary. The density of states is enhanced at low energies. The number of localized states depends on the degree of misfit across the boundary. A continuum of zero energy states appears at certain values of the angle rotation.