# Competing superconducting phases in interacting two-dimensional electron gas with strong Rashba spin-orbit coupling

## TL;DR

This paper investigates how strong Rashba spin-orbit coupling influences superconducting phases in an interacting two-dimensional electron gas, revealing competing pairing symmetries and potential topological superconductivity.

## Contribution

It provides a detailed phase diagram showing the interplay of charge and spin fluctuations in determining pairing symmetries in a Rashba-coupled extended Hubbard model.

## Key findings

- $d_{xy}$ and $d_{x^2-y^2}$ pairing symmetries are prominent
- Higher angular momentum pairings emerge due to strong fluctuations
- Potential for topological and triplet superconductivity is discussed

## Abstract

In this work we study interacting electrons on square lattice in the presence of strong Rashba spin-orbit interaction. The spin-orbit term forces the time-reversal electron states to be paired in even Cooper channels. For concreteness, we only consider the repulsive onsite Hubbard and nearest-neighbor coulomb interactions, the so called extended Hubbard model. To examine the superconducting instability we obtain the effective interaction between electrons within the random phase approximation and treat the pairing instabilities driven by charge and spin fluctuations and their combined effects. We mapped out the phase diagram of the model in terms of interactions and electron fillings, and found that while the $d_{xy}$ and $d_{x^2-y^2}$ symmetries are the most likely pairing symmetries driven by charge and spin fluctuations, respectively, the strong effect of both fluctuations yields higher angular momentum Cooper instability. The possibility of topological superconductivity and triplet pairing is also discussed.