Spin-orbit-assisted electron pairing in 1D waveguides

TL;DR

This paper investigates how spin-orbit coupling can be engineered to enhance electron pairing in one-dimensional waveguides, with implications for quantum transport and potential applications in oxide interfaces and cold atom systems.

Contribution

It demonstrates that engineered spin-orbit coupling can generate and boost electron pairing in 1D systems, supported by a mean-field model and experimental correlations.

Findings

SOC can be reduced in 1D confinement at interfaces.

Engineered SOC enhances spin-singlet and triplet pairing.

Results align with recent experimental observations.

Abstract

Understanding and controlling the transport properties of interacting fermions is a key forefront in quantum physics across a variety of experimental platforms. Motivated by recent experiments in 1D electron channels written on the $\mathrm{LaAlO_3}$/$\mathrm{SrTiO_3}$ interface, we analyse how the presence of different forms of spin-orbit coupling (SOC) can enhance electron pairing in 1D waveguides. We first show how the intrinsic Rashba SOC felt by electrons at interfaces such as $\mathrm{LaAlO_3}$/$\mathrm{SrTiO_3}$ can be reduced when they are confined in 1D. Then, we discuss how SOC can be engineered, and show using a mean-field Hartree-Fock-Bogoliubov model that SOC can generate and enhance spin-singlet and triplet electron pairing. Our results are consistent with two recent sets of experiments [Briggeman et al., arXiv:1912.07164; Sci. Adv. 6, eaba6337 (2020)] that are believed to engineer the forms of SOC investigated in this work, which suggests that metal-oxide heterostructures constitute attractive platforms to control the collective spin of electron bound states. However, our findings could also be applied to other experimental platforms involving spinful fermions with attractive interactions, such as cold atoms.