Time-reversal symmetry breaking superconductivity in the presence of loop-current fluctuations

Fuente: arXiv
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Autori principali: Fan, Zenghui, Ma, Runyu, Chesi, Stefano, Wu, Congjun, Ma, Tianxing
Natura: Preprint
Pubblicazione: 2025
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author Fan, Zenghui
Ma, Runyu
Chesi, Stefano
Wu, Congjun
Ma, Tianxing
author_facet Fan, Zenghui
Ma, Runyu
Chesi, Stefano
Wu, Congjun
Ma, Tianxing
contents Loop currents have been proposed in various superconductors and recently confirmed in kagome materials, raising a fundamental question regarding their intrinsic connection to superconductivity. Here, we study a sign-problem-free bilayer $t-J_{\perp}-V$ model hosting a spontaneous interlayer loop-current parent state, and explore the interplay between loop-current fluctuations and superconductivity using unbiased projector quantum Monte Carlo simulations. Near half-filling, unbiased interlayer interactions induce spontaneous loop currents that break time-reversal symmetry. Upon hole doping, the loop-current order is suppressed, and interlayer $s$-wave superconductivity emerges where loop-current fluctuations become dominant. We establish a phase diagram revealing a transition from the loop-current parent to a superconducting state, reminiscent of the evolution from an antiferromagnetic parent to superconductivity in cuprates. Strikingly, a coexisting regime emerges near the phase boundary, yielding time-reversal-symmetry-breaking superconductivity. Our study reveals an intrinsic connection between loop currents and superconductivity, and identifies a promising mechanism for time-reversal symmetry breaking in superconductors. Furthermore, our results offer insights into unconventional superconductivity in loop-current systems and establish a minimal theoretical framework for understanding time-reversal symmetry breaking in bilayer correlated electron systems.
format Preprint
id arxiv_https___arxiv_org_abs_2510_19313
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Time-reversal symmetry breaking superconductivity in the presence of loop-current fluctuations
Fan, Zenghui
Ma, Runyu
Chesi, Stefano
Wu, Congjun
Ma, Tianxing
Superconductivity
Strongly Correlated Electrons
Loop currents have been proposed in various superconductors and recently confirmed in kagome materials, raising a fundamental question regarding their intrinsic connection to superconductivity. Here, we study a sign-problem-free bilayer $t-J_{\perp}-V$ model hosting a spontaneous interlayer loop-current parent state, and explore the interplay between loop-current fluctuations and superconductivity using unbiased projector quantum Monte Carlo simulations. Near half-filling, unbiased interlayer interactions induce spontaneous loop currents that break time-reversal symmetry. Upon hole doping, the loop-current order is suppressed, and interlayer $s$-wave superconductivity emerges where loop-current fluctuations become dominant. We establish a phase diagram revealing a transition from the loop-current parent to a superconducting state, reminiscent of the evolution from an antiferromagnetic parent to superconductivity in cuprates. Strikingly, a coexisting regime emerges near the phase boundary, yielding time-reversal-symmetry-breaking superconductivity. Our study reveals an intrinsic connection between loop currents and superconductivity, and identifies a promising mechanism for time-reversal symmetry breaking in superconductors. Furthermore, our results offer insights into unconventional superconductivity in loop-current systems and establish a minimal theoretical framework for understanding time-reversal symmetry breaking in bilayer correlated electron systems.
title Time-reversal symmetry breaking superconductivity in the presence of loop-current fluctuations
topic Superconductivity
Strongly Correlated Electrons
url https://arxiv.org/abs/2510.19313