Recent experiments with nanopatterned thin films revealed an unusual quantum superconductor to metal phase transition (QSMT) with a linear in temperature resistivity. In contrast, most known examples of such transitions and standard theoretical considerations predict a temperature-independent sheet resistance of order $R_Q = \frac{\hbar}{e^2}$ . We propose an effective theory of a disordered superconductor which features a QSMT with robust $T$ linear resistivity at the critical point. The crucial ingredient in our model is spatial disorder in the pairing interaction. Such random pairing mirrors the emergent phase disorder seen in a recent mean field study of a microscopic $d$ -wave superconductor subject to potential disorder. We also make the prediction that in such systems the diamagnetic susceptibility diverges as $\log\fracΛ{T}$ , which starkly differs from the power law divergence in standard XY transitions.Recent experiments with nanopatterned thin films revealed an unusual quantum superconductor to metal phase transition (QSMT) with a linear in temperature resistivity. In contrast, most known examples of such transitions and standard theoretical considerations predict a temperature-independent sheet resistance of order $R_Q = \frac{\hbar}{e^2}$. We propose an effective theory of a disordered superconductor which features a QSMT with robust $T$ linear resistivity at the critical point. The crucial ingredient in our model is spatial disorder in the pairing interaction. Such random pairing mirrors the emergent phase disorder seen in a recent mean field study of a microscopic $d$-wave superconductor subject to potential disorder. We also make the prediction that in such systems the diamagnetic susceptibility diverges as $\log\fracΛ{T}$, which starkly differs from the power law divergence in standard XY transitions.

arXiv:2401.17353Jan 30, 20240 citations

Metal-Insulator-Superconductor Transition in Two-Channel Interacting Many-Body Systems

Theja N. De Silva

Bulletin of the American Physical SocietyMar 5, 20190 citations

Metallic phases from disordered (2+1)-dimensional quantum electrodynamics

Pallab Goswami, Hart Goldman, S. Raghu

Metallic phases have been observed in several disordered two-dimensional (2D) systems, including thin films near superconductor-insulator transitions and quantum Hall systems near plateau transitions. The existence of 2D metallic phases at zero temperature generally requires an interplay of disorder and interaction effects. Consequently, experimental observations of 2D metallic behavior have largely defied explanation. We formulate a general stability criterion for strongly interacting, massless Dirac fermions against disorder, which describe metallic ground states with vanishing density of states. We show that (2+1)-dimensional quantum electrodynamics ( ${\mathrm{QED}}_{3}$ ) with a large, even number of fermion flavors remains metallic in the presence of weak scalar potential disorder due to the dynamic screening of disorder by gauge fluctuations. We also show that ${\mathrm{QED}}_{3}$ with weak mass disorder exhibits a stable, dirty metallic phase in which both interactions and disorder play important roles.Metallic phases have been observed in several disordered two-dimensional (2D) systems, including thin films near superconductor-insulator transitions and quantum Hall systems near plateau transitions. The existence of 2D metallic phases at zero temperature generally requires an interplay of disorder and interaction effects. Consequently, experimental observations of 2D metallic behavior have largely defied explanation. We formulate a general stability criterion for strongly interacting, massless Dirac fermions against disorder, which describe metallic ground states with vanishing density of states. We show that (2+1)-dimensional quantum electrodynamics (${\mathrm{QED}}_{3}$) with a large, even number of fermion flavors remains metallic in the presence of weak scalar potential disorder due to the dynamic screening of disorder by gauge fluctuations. We also show that ${\mathrm{QED}}_{3}$ with weak mass disorder exhibits a stable, dirty metallic phase in which both interactions and disorder play important roles.

arXiv:1701.07828Physical review. B./Physical review. BJun 26, 201726 citations

Ginzburg-Landau Theory for Confined Thin-Film Superconductors

Giovanni A. Ummarino, Alessio Zaccone

We develop a Ginzburg-Landau theory for superconducting thin films under quantum confinement. Starting from the Ginzburg-Landau theory and the recently developed confinement theory of metallic thin films, explicit analytical expressions are derived for the coherence length, penetration depth, electronic mean free path, and Ginzburg-Landau parameter in confined geometries. The central result is that quantum confinement directly renormalizes the intrinsic superconducting coherence length through confinement-induced modifications of the electronic density of states and Fermi energy. This effect is absent in conventional thin-film transport theories based solely on surface scattering. As a consequence, confinement simultaneously suppresses the coherence length and enhances the penetration depth, thereby driving superconductors toward stronger type-II behavior over a broad thickness range. The interplay between quantum confinement and disorder can also produce reentrant type-I/type-II crossovers. The theory predicts a crossover regime in which confinement-induced renormalization of superconducting length scales and transport scattering become strongly intertwined. Comparison with recent penetration-depth measurements in Al thin films shows that the observed enhancement of the penetration depth originates from the interplay between confinement-induced renormalization of the coherence length and suppression of the effective mean free path by surface and disorder scattering. The results establish a direct connection between quantum confinement and superconducting electrodynamics in confined metallic films.We develop a Ginzburg-Landau theory for superconducting thin films under quantum confinement. Starting from the Ginzburg-Landau theory and the recently developed confinement theory of metallic thin films, explicit analytical expressions are derived for the coherence length, penetration depth, electronic mean free path, and Ginzburg-Landau parameter in confined geometries. The central result is that quantum confinement directly renormalizes the intrinsic superconducting coherence length through confinement-induced modifications of the electronic density of states and Fermi energy. This effect is absent in conventional thin-film transport theories based solely on surface scattering. As a consequence, confinement simultaneously suppresses the coherence length and enhances the penetration depth, thereby driving superconductors toward stronger type-II behavior over a broad thickness range. The interplay between quantum confinement and disorder can also produce reentrant type-I/type-II crossovers. The theory predicts a crossover regime in which confinement-induced renormalization of superconducting length scales and transport scattering become strongly intertwined. Comparison with recent penetration-depth measurements in Al thin films shows that the observed enhancement of the penetration depth originates from the interplay between confinement-induced renormalization of the coherence length and suppression of the effective mean free path by surface and disorder scattering. The results establish a direct connection between quantum confinement and superconducting electrodynamics in confined metallic films.

cond-mat.supr-conCross-listedarXiv:2605.10686May 12, 2026

Monte Carlo simulations of a disordered superconductor-metal quantum phase transition

Ahmed K. Ibrahim, Thomas Vojta

arXiv:1808.00094The European Physical Journal BDec 1, 20181 citation

R_Q = \frac{\hbar}{e^2}

. We propose an effective theory of a disordered superconductor which features a QSMT with robust

T

linear resistivity at the critical point. The crucial ingredient in our model is spatial disorder in the pairing interaction. Such random pairing mirrors the emergent phase disorder seen in a recent mean field study of a microscopic

d

-wave superconductor subject to potential disorder. We also make the prediction that in such systems the diamagnetic susceptibility diverges as

\log\fracΛ{T}

, which starkly differs from the power law divergence in standard XY transitions.

{\mathrm{QED}}_{3}

) with a large, even number of fermion flavors remains metallic in the presence of weak scalar potential disorder due to the dynamic screening of disorder by gauge fluctuations. We also show that

{\mathrm{QED}}_{3}

with weak mass disorder exhibits a stable, dirty metallic phase in which both interactions and disorder play important roles.