Tuning Rashba and Dresselhaus spin-orbit couplings: Effects on singlet and triplet condensation with Fermi atoms

TL;DR

This paper explores how tuning Rashba and Dresselhaus spin-orbit couplings affects singlet and triplet pair condensates in a Fermi gas, revealing that mixing these couplings alters pairing behaviors across the BCS-BEC crossover.

Contribution

It provides a detailed analysis of the effects of combined Rashba and Dresselhaus couplings on pair condensation in Fermi gases, highlighting the impact on singlet and triplet pairing in different regimes.

Findings

Mixing Rashba and Dresselhaus couplings decreases singlet pairing.

Triplet pairing is suppressed in the BCS regime and increased in the BEC regime when couplings are mixed.

Maximum condensate fraction occurs with only one type of coupling, Rashba or Dresselhaus.

Abstract

We investigate the pair condensation of a two-spin-component Fermi gas in the presence of both Rashba and Dresselhaus spin-orbit couplings. We calculate the condensate fraction in the BCS-BEC crossover both in two and in three dimensions by taking into account singlet and triplet pairings. These quantities are studied by varying the spin-orbit interaction from the case with the only Rashba to the equal-Rashba-Dresselhaus one. We find that, by mixing the two couplings, the singlet pairing decreases while the triplet pairing is suppressed in the BCS regime and increased in the BEC regime, both in two and three dimensions. At fixed spin-orbital strength, the greatest total condensate fraction is obtained when only one coupling (only Rashba or only Dresselhaus) is present.