We consider the effect of weak nonmagnetic disorder on two chains of interacting fermions (with and without spins) coupled by interchain hopping. For the spinless case, interchain hopping increases localization for repulsive interactions but stabilizes the $s$ -wave superconducting phase for attractive interactions. For the case with spin, the $d$ -wave phase arising from purely repulsive interactions in the clean system is destroyed by an infinitesimal disorder, while for attractive interactions, the $s$ -wave superconductivity is more resistant to disorder than in the one-chain case. In each case we compute the localization length and the conductivity.We consider the effect of weak nonmagnetic disorder on two chains of interacting fermions (with and without spins) coupled by interchain hopping. For the spinless case, interchain hopping increases localization for repulsive interactions but stabilizes the $s$-wave superconducting phase for attractive interactions. For the case with spin, the $d$-wave phase arising from purely repulsive interactions in the clean system is destroyed by an infinitesimal disorder, while for attractive interactions, the $s$-wave superconductivity is more resistant to disorder than in the one-chain case. In each case we compute the localization length and the conductivity.

arXiv:cond-mat/9507029Physical review. B, Condensed matterApr 15, 199627 citations

Superconductivity from purely repulsive forces

H. Capellmann

ZhETF Pisma RedaktsiiuNov 1, 19950 citations

Intertwined Superconductivity and Magnetism from Repulsive Interactions in Kondo Bilayers

Clara S. Weber, Dominik Kiese, Dante Marvin Kennes +1 more

While superconductors are conventionally established by attractive interactions, higher-temperature mechanisms for emergent electronic pairing from strong repulsive electron-electron interactions remain under considerable scrutiny. Here, we establish a strong-coupling mechanism for intertwined superconductivity and magnetic order from purely repulsive interactions in a Kondo-like bilayer system, composed of a two-dimensional Mott insulator coupled to a layer of weakly-interacting itinerant electrons. Combining large scale DMRG and Monte Carlo simulations, we find that superconductivity persists and coexists with magnetism over a wide range of interlayer couplings. We classify the resulting rich phase diagram and find 2-rung antiferromagnetic and 4-rung antiferromagnetic order in one-dimensional systems along with a phase separation regime, while finding that superconductivity coexists with either antiferromagnetic or ferromagnetic order in two dimensions. Remarkably, the model permits a rigorous strong-coupling analysis via localized spins coupled to charge-2e bosons through Kugel-Khomskii interactions, capturing the pairing mechanism in the presence of magnetism due to emergent attractive interactions. Our numerical analysis reveals that pairing remains robust well beyond the strong-coupling regime, establishing a new mechanism for superconductivity in coupled weakly- and strongly-interacting electron systems, relevant for infinite-layer nickelates and superconductivity in moire multilayer heterostructures.While superconductors are conventionally established by attractive interactions, higher-temperature mechanisms for emergent electronic pairing from strong repulsive electron-electron interactions remain under considerable scrutiny. Here, we establish a strong-coupling mechanism for intertwined superconductivity and magnetic order from purely repulsive interactions in a Kondo-like bilayer system, composed of a two-dimensional Mott insulator coupled to a layer of weakly-interacting itinerant electrons. Combining large scale DMRG and Monte Carlo simulations, we find that superconductivity persists and coexists with magnetism over a wide range of interlayer couplings. We classify the resulting rich phase diagram and find 2-rung antiferromagnetic and 4-rung antiferromagnetic order in one-dimensional systems along with a phase separation regime, while finding that superconductivity coexists with either antiferromagnetic or ferromagnetic order in two dimensions. Remarkably, the model permits a rigorous strong-coupling analysis via localized spins coupled to charge-2e bosons through Kugel-Khomskii interactions, capturing the pairing mechanism in the presence of magnetism due to emergent attractive interactions. Our numerical analysis reveals that pairing remains robust well beyond the strong-coupling regime, establishing a new mechanism for superconductivity in coupled weakly- and strongly-interacting electron systems, relevant for infinite-layer nickelates and superconductivity in moire multilayer heterostructures.

arXiv:2408.02847Aug 5, 20240 citations

Superconductivity in strongly correlated systems for local repulsive interactions

Francisco Neto, Humberto Silva, Griffith M. Rufo +4 more

Jan 1, 20260 citations

Continuous-Time Quantum Monte Carlo Study of Strong Coupling Superconductivity in Holstein–Hubbard Model

Satoshi Yamazaki, Shintaro Hoshino, Yoshio Kuramoto

Superconducting transition temperature is studied in the strong-coupling region of the Holstein-Hubbard model that includes both electron-phonon and Coulomb interactions.By combining the dynamical mean field theory with the continuous-time quantum Monte Carlo method, transition temperature is derived numerically.Without Coulomb interaction, our calculation reproduces analytic expressions of the transition temperature for weak and strong coupling limits of electron-phonon interaction.When electron-phonon coupling is strong enough, Coulomb repulsion enhances superconductivity, in contrast to the weak coupling case.The enhancement is due to coherent motion of superconducting pairs that reduce the Coulomb repulsive energy of almost localized electrons.Superconducting transition temperature is studied in the strong-coupling region of the Holstein-Hubbard model that includes both electron-phonon and Coulomb interactions.By combining the dynamical mean field theory with the continuous-time quantum Monte Carlo method, transition temperature is derived numerically.Without Coulomb interaction, our calculation reproduces analytic expressions of the transition temperature for weak and strong coupling limits of electron-phonon interaction.When electron-phonon coupling is strong enough, Coulomb repulsion enhances superconductivity, in contrast to the weak coupling case.The enhancement is due to coherent motion of superconducting pairs that reduce the Coulomb repulsive energy of almost localized electrons.

International Conference on Strongly Correlated Electron Systems (SCES)Jun 16, 20142 citations

s

-wave superconducting phase for attractive interactions. For the case with spin, the

d

-wave phase arising from purely repulsive interactions in the clean system is destroyed by an infinitesimal disorder, while for attractive interactions, the

s

-wave superconductivity is more resistant to disorder than in the one-chain case. In each case we compute the localization length and the conductivity.