Spin-triplet superconductivity from quantum-geometry-induced ferromagnetic fluctuation

TL;DR

This paper demonstrates that quantum geometry can induce ferromagnetic fluctuations, which in turn mediate spin-triplet superconductivity, especially near non-Kramers degeneracies, revealing a new mechanism for unconventional pairing.

Contribution

It identifies quantum geometry as a key factor in promoting ferromagnetic fluctuations and spin-triplet superconductivity, providing a new theoretical framework for understanding unconventional superconductors.

Findings

Quantum geometry induces ferromagnetic fluctuations near non-Kramers degeneracies.

Spin-triplet superconductivity is mediated by quantum-geometry-induced ferromagnetic fluctuations.

The linearized gap equation confirms the role of quantum geometry in pairing mechanism.

Abstract

We show that quantum geometry induces ferromagnetic fluctuation resulting in spin-triplet superconductivity. The criterion for ferromagnetic fluctuation is clarified by analyzing contributions from the effective mass and quantum geometry. When the non-Kramers band degeneracy is present near the Fermi surface, the Fubini-Study quantum metric strongly favors ferromagnetic fluctuation. Solving the linearized gap equation with the effective interaction obtained by the random phase approximation, we show that the spin-triplet superconductivity is mediated by quantum-geometry-induced ferromagnetic fluctuation.