Parity-mixing superconducting phase in the Rashba-Hubbard model and its topological properties from dynamical mean field theory

TL;DR

This study explores parity-mixing superconductivity with topological features in the Rashba-Hubbard model using CDMFT, revealing a mixed singlet-triplet phase with nontrivial topology influenced by doping and magnetic fields.

Contribution

It demonstrates the emergence of parity-mixed superconductivity with topological properties in the Rashba-Hubbard model, analyzed through Cellular Dynamical Mean-Field Theory.

Findings

Mixed singlet $d$-wave and triplet $p$-wave superconductivity found across doping levels.

Nonzero bulk Chern number indicates topological superconducting phase.

Superconducting gap suppression suggests a possible topological transition.

Abstract

We investigate parity-mixing superconductivity in the two-dimensional Hubbard model with Rashba spin-orbit coupling, using Cellular Dynamical Mean-Field Theory (CDMFT). A superconducting state with mixed singlet $d$-wave and triplet $p$-wave character is found in a wide range of doping. The singlet component decreases with the amplitude of the Rashba spin-orbit coupling, whereas the triplet component increases, but both disappear at about 20\% doping. The effect of a Zeeman field is also investigated; it tends to suppress both types of superconductivity, but induces nontrivial topological properties: the computed bulk Chern number is nonzero in the mixed superconductivity phase, at least in the underdoped region. A strong suppression of the excitation gap occurs slightly after optimal doping; this might be the sign of a topological transition within the superconducting dome.