Twin boundaries in d-wave superconductors

TL;DR

This paper numerically investigates twin boundaries in orthorhombic d-wave superconductors, revealing conditions under which an induced s-wave component breaks time-reversal symmetry, with results compared to tunneling experiments.

Contribution

It introduces a numerical study of twin boundaries in d-wave superconductors using Bogoliubov-deGennes formalism, highlighting the emergence of complex order parameters and symmetry breaking.

Findings

Induced s-wave component can break time-reversal symmetry at low temperatures.

The temperature and magnitude of the complex component depend on electron density.

Results align with recent tunneling measurements.

Abstract

Twin boundaries in orthorhombic d-wave superconductors are investigated numerically using the Bogoliubov-deGennes formalism within the context of an extended Hubbard model. The twin boundaries are represented by tetragonal regions of variable width, with a reduced chemical potential. For sufficiently large twin boundary width and change in chemical potential, an induced s-wave component may break time-reversal symmetry at a low temperature. This temperature, and the magnitude of the complex component, are found to depend strongly on electron density. The results are compared with recent tunneling measurements.