Superfluid Stiffness and Josephson Quantum Capacitance: Adiabatic Approach and Topological Effects

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Hauptverfasser: Wang, Jun-Ang, Assili, Mohamed, Kotetes, Panagiotis
Format: Preprint
Veröffentlicht: 2023
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author Wang, Jun-Ang
Assili, Mohamed
Kotetes, Panagiotis
author_facet Wang, Jun-Ang
Assili, Mohamed
Kotetes, Panagiotis
contents We bring forward a unified framework for the study of the superfluid stiffness and the quantum capacitance of superconducting platforms exhibiting conventional spin-singlet pairing. We focus on systems which in their normal phase contain topological band touching points or crossings, while in their superconducting regime feature a fully gapped energy spectrum. Our unified description relies on viewing these two types of physical quantities as the charge current and density response coefficients obtained for ``slow" spatiotemporal variations of the superconducting phase. Within our adiabatic formalism, the two coefficients are given in terms of Berry curvatures defined in synthetic spaces. Our work lays the foundations for the systematic description of topological diagonal superfluid responses induced by singularities dictating the synthetic Berry curvatures. We exemplify our approach for concrete one- and two-dimensional models of superconducting topological (semi)metals. We discuss topological phenomena which arise in the superfluid stiffness of bulk systems and the quantum capacitance of Josephson junctions. We show that both coefficients become proportional to a topological invariant which counts the number of topological touchings/crossings of the normal phase band structure. These topological effects can be equivalently viewed as manifestations of chiral anomaly. Our predictions appear experimentally testable in topological semimetals with proximity-induced pairing, such as in graphene-superconductor hybrids at charge neutrality.
format Preprint
id arxiv_https___arxiv_org_abs_2310_12223
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Superfluid Stiffness and Josephson Quantum Capacitance: Adiabatic Approach and Topological Effects
Wang, Jun-Ang
Assili, Mohamed
Kotetes, Panagiotis
Superconductivity
Mesoscale and Nanoscale Physics
Materials Science
We bring forward a unified framework for the study of the superfluid stiffness and the quantum capacitance of superconducting platforms exhibiting conventional spin-singlet pairing. We focus on systems which in their normal phase contain topological band touching points or crossings, while in their superconducting regime feature a fully gapped energy spectrum. Our unified description relies on viewing these two types of physical quantities as the charge current and density response coefficients obtained for ``slow" spatiotemporal variations of the superconducting phase. Within our adiabatic formalism, the two coefficients are given in terms of Berry curvatures defined in synthetic spaces. Our work lays the foundations for the systematic description of topological diagonal superfluid responses induced by singularities dictating the synthetic Berry curvatures. We exemplify our approach for concrete one- and two-dimensional models of superconducting topological (semi)metals. We discuss topological phenomena which arise in the superfluid stiffness of bulk systems and the quantum capacitance of Josephson junctions. We show that both coefficients become proportional to a topological invariant which counts the number of topological touchings/crossings of the normal phase band structure. These topological effects can be equivalently viewed as manifestations of chiral anomaly. Our predictions appear experimentally testable in topological semimetals with proximity-induced pairing, such as in graphene-superconductor hybrids at charge neutrality.
title Superfluid Stiffness and Josephson Quantum Capacitance: Adiabatic Approach and Topological Effects
topic Superconductivity
Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2310.12223