Phase diagram of a d-wave superconductor with Anderson impurities

TL;DR

This paper investigates the phase diagram of a d-wave superconductor with Anderson impurities at zero temperature, revealing how impurity interactions influence superconducting-normal transitions and identifying conditions for multiple phase changes.

Contribution

It provides a self-consistent analysis of the phase diagram considering impurity interactions using the slave boson method, highlighting new transition behaviors based on impurity parameters.

Findings

One superconducting-normal transition for fixed impurity level in the Kondo limit.

Three transitions occur when impurity level is near the Fermi energy and impurity concentration exceeds a threshold.

Two transitions are observed when varying impurity level depth at fixed hybridization and above a certain impurity concentration.

Abstract

We present a self-consistent solution for a model of a d-wave superconductor with finite concen- tration of Anderson impurities at zero temperature using the slave boson method. We show how the phase diagram depends on the strength of interaction between impurity and extended states. For fixed impurity level energy $E_0$ in the Kondo limit there is one superconducting-normal state transition for all impurity concentrations $n$. When $E_0$ is close the Fermi energy there are three such transitions for impurity concentration exceeding certain minimum value $n(\Gamma_0,E_0)$. If hybridization $\Gamma_0$ is fixed and the depth of the impurity level is varied, there are always two transitions for concentration above $n(\Gamma_0,E_0)$.