Effects of longer-range interactions on unconventional superconductivity

TL;DR

This paper investigates how longer-range electron-electron interactions influence unconventional superconductivity, showing that while they can suppress the critical temperature, superconductivity persists under realistic conditions.

Contribution

It provides asymptotically exact weak-coupling results and RDMRG analysis for extended Hubbard models, demonstrating the robustness of unconventional superconductivity against longer-range interactions.

Findings

Longer-range interactions suppress $T_c$ in some pairing channels.

Superconductivity is not entirely destroyed by extended interactions.

Electron-electron interactions can still induce unconventional superconductivity.

Abstract

We analyze the effect of the non-vanishing range of electron-electron repulsion on the mechanism of unconventional superconductivity. We present asymptotically exact weak-coupling results for dilute electrons in the continuum and for the 2D extended Hubbard model, as well as density-matrix renormalization group results for the two-leg extended Hubbard model at intermediate couplings, and approximate results for the case of realistically screened Coulomb interactions. We show that $T_c$ is generally suppressed in some pairing channels as longer range interactions increase in strength, but superconductivity is not destroyed. Our results confirm that electron-electron interaction can lead to unconventional superconductivity under physically realistic circumstances.