A Replica-BCS theory for dirty superconductors

Fuente: arXiv
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Autores principales: Lau, Yat Fan, Ng, Tai Kai
Formato: Preprint
Publicado: 2023
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author Lau, Yat Fan
Ng, Tai Kai
author_facet Lau, Yat Fan
Ng, Tai Kai
contents In this paper, we revisit the problem of dirty superconductors using a replica-symmetric BCS (RS-BCS) theory. We apply the RS-BCS theory to dirty superconductor grains of size $L^d$, where $L$ is the localization length and $d$ is the dimension of the system, assuming that the macroscopic system is composed of weakly coupled grains. Besides disordered potential, We also consider the case where regions with opposite signs of interaction exist in the grains, with net attractive interaction between electrons. Within the RS-BCS mean field theory, the system phase diagram, single-particle tunneling density of states and the superfluid density are computed within the RS-BCS theory for different strengths of disorder, We show that our result agrees qualitatively with previous numerical studies in the case with pure attractive interaction, and that a Cooper-pair-glass state may exist when regions with opposite sign of interaction exists and the net interaction between electrons is close to zero. The plausible relevance of our result to the anomalous metal state is discussed.
format Preprint
id arxiv_https___arxiv_org_abs_2311_14914
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A Replica-BCS theory for dirty superconductors
Lau, Yat Fan
Ng, Tai Kai
Superconductivity
Disordered Systems and Neural Networks
In this paper, we revisit the problem of dirty superconductors using a replica-symmetric BCS (RS-BCS) theory. We apply the RS-BCS theory to dirty superconductor grains of size $L^d$, where $L$ is the localization length and $d$ is the dimension of the system, assuming that the macroscopic system is composed of weakly coupled grains. Besides disordered potential, We also consider the case where regions with opposite signs of interaction exist in the grains, with net attractive interaction between electrons. Within the RS-BCS mean field theory, the system phase diagram, single-particle tunneling density of states and the superfluid density are computed within the RS-BCS theory for different strengths of disorder, We show that our result agrees qualitatively with previous numerical studies in the case with pure attractive interaction, and that a Cooper-pair-glass state may exist when regions with opposite sign of interaction exists and the net interaction between electrons is close to zero. The plausible relevance of our result to the anomalous metal state is discussed.
title A Replica-BCS theory for dirty superconductors
topic Superconductivity
Disordered Systems and Neural Networks
url https://arxiv.org/abs/2311.14914