Superconductivity in repulsive Fermi-systems at low density

TL;DR

This paper explores the potential for p-wave and d-wave superconductivity in various low-density Fermi systems, showing how critical temperatures can be enhanced under certain conditions, with implications for high-temperature superconductivity.

Contribution

It demonstrates the possibility of p-wave pairing in low-density repulsive Fermi systems and discusses mechanisms to increase critical temperatures, including spin polarization and multi-band effects.

Findings

P-wave pairing can occur at low densities in various models.

Critical temperature can reach 1-5K in spin-polarized or two-band systems.

D-wave pairing and high-Tc superconductivity are briefly discussed.

Abstract

In the large variety of models such as 3D and 2D Fermi-gas model with hard-core repulsion, 3D and 2D Hubbard model, and Shubin-Vonsovsky model we demonstrate the possibility of triplrt p-wave pairing at low electron density. We show that the critical temperature of the p-wave pairing can be strongly increased in a spin-polarized case or in a two-band situation already at low density and reach experimentally observable values of (1-5)K. We also discuss briefly d-wave pairing and high-Tc superconductivity with Tc~100K which arises in the t-J model in the range of parameters realistic for cuprates.