Spontaneous time-reversal symmetry breaking by disorder in superconductors

Fuente: arXiv
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Main Authors: Andersen, Brian M., Kreisel, Andreas, Hirschfeld, P. J.
Format: Preprint
Published: 2023
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author Andersen, Brian M.
Kreisel, Andreas
Hirschfeld, P. J.
author_facet Andersen, Brian M.
Kreisel, Andreas
Hirschfeld, P. J.
contents A growing number of superconducting materials display evidence for spontaneous time-reversal symmetry breaking (TRSB) below their critical transition temperatures. Precisely what this implies for the nature of the superconducting ground state of such materials, however, is often not straightforward to infer. We review the experimental status and survey different theoretical mechanisms for the generation of TRSB in superconductors. In cases where a TRSB complex combination of two superconducting order parameter components is realized, defects, dislocations and sample edges may generate superflow patterns that can be picked up by magnetic probes. However, even single-component condensates that do not break time-reversal symmetry in their pure bulk phases can also support signatures of magnetism inside the superconducting state. This includes, for example, the generation of localized orbital current patterns or spin-polarization near atomic-scale impurities, twin boundaries and other defects. Signals of TRSB may also arise from a superconductivity-enhanced Ruderman-Kittel-Kasuya-Yosida exchange coupling between magnetic impurity moments present in the normal state. We discuss the relevance of these different mechanisms for TRSB in light of recent experiments on superconducting materials of current interest.
format Preprint
id arxiv_https___arxiv_org_abs_2312_08099
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Spontaneous time-reversal symmetry breaking by disorder in superconductors
Andersen, Brian M.
Kreisel, Andreas
Hirschfeld, P. J.
Superconductivity
Strongly Correlated Electrons
A growing number of superconducting materials display evidence for spontaneous time-reversal symmetry breaking (TRSB) below their critical transition temperatures. Precisely what this implies for the nature of the superconducting ground state of such materials, however, is often not straightforward to infer. We review the experimental status and survey different theoretical mechanisms for the generation of TRSB in superconductors. In cases where a TRSB complex combination of two superconducting order parameter components is realized, defects, dislocations and sample edges may generate superflow patterns that can be picked up by magnetic probes. However, even single-component condensates that do not break time-reversal symmetry in their pure bulk phases can also support signatures of magnetism inside the superconducting state. This includes, for example, the generation of localized orbital current patterns or spin-polarization near atomic-scale impurities, twin boundaries and other defects. Signals of TRSB may also arise from a superconductivity-enhanced Ruderman-Kittel-Kasuya-Yosida exchange coupling between magnetic impurity moments present in the normal state. We discuss the relevance of these different mechanisms for TRSB in light of recent experiments on superconducting materials of current interest.
title Spontaneous time-reversal symmetry breaking by disorder in superconductors
topic Superconductivity
Strongly Correlated Electrons
url https://arxiv.org/abs/2312.08099