Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1105.2041 · Physical Review B

Spin-orbit coupling induced enhancement of superconductivity in a two-dimensional repulsive gas of fermions

Oskar Vafek, Luyang Wang

Published Nov 3, 2011• 16 citations
arXivHTMLPDF

Abstract

We study a model of a two-dimensional repulsive Fermi gas with Rashba spin-orbit coupling ${\ensuremath{\alpha}}_{R}$ and investigate the superconducting instability using the renormalization-group approach. We find that, in general, superconductivity is enhanced as the dimensionless ratio $\frac{1}{2}m{\ensuremath{\alpha}}_{R}^{2}/{E}_{F}$ increases, resulting in unconventional superconducting states which break time-reversal symmetry.

DOI
10.1103/physrevb.84.172501

Related papers

Superconductivity in a two-dimensional repulsive Rashba gas at low electron density

Luyang Wang

We study the superconducting instability and the resulting superconducting states in a two-dimensional repulsive Fermi gas with Rashba spin–orbit coupling at low electron density (namely the Fermi energy E F is lower than the energy E R of the Dirac point induced by Rashba coupling). We find that superconductivity is enhanced as the dimensionless Fermi energy ( ) decreases, due to two reasons. First, the density of states at increases as . Second, the particle–hole bubble becomes more anisotropic, resulting in an increasing effective attraction. The superconducting state is always in the total angular momentum (or ) channel with Chern number C = 4 (or ), breaking time reversal symmetry spontaneously. Although a putative Leggett mode is expected due to the two-gap nature of the superconductivity, we find that it is always damped. More importantly, once a sufficiently large Zeeman coupling is applied to the superconducting state, the Chern number can be tuned to be ±1 and Majorana zero modes exist in the vortex cores.

arXiv:1612.06613•Journal of Physics Communications•Sep 1, 2017•2 citations

Polarization of a quasi-two-dimensional repulsive Fermi gas with Rashba spin-orbit coupling: A variational study

Alberto Ambrosetti, Giovanni Lombardi, Luca Salasnich +2 more

Motivated by the remarkable experimental control of synthetic gauge fields in ultracold atomic systems, we investigate the effect of an artificial Rashba spin-orbit coupling on the spin polarization of a two-dimensional repulsive Fermi gas. By using a variational many-body wave function, based on a suitable spinorial structure, we find that the polarization properties of the system are indeed controlled by the interplay between spin-orbit coupling and repulsive interaction. In particular, two main effects are found: (1) The Rashba coupling determines a gradual increase of the degree of polarization beyond the critical repulsive interaction strength, at variance with conventional two-dimensional Stoner instability. (2) The critical interaction strength, above which finite polarization is developed, shows a dependence on the Rashba coupling, i.e., it is enhanced in case the Rashba coupling exceeds a critical value. A simple analytic expression for the critical interaction strength is further derived in the context of our variational formulation, which allows for a straightforward and insightful analysis of the present problem.

arXiv:1410.5938•Physical Review A•Oct 15, 2014•11 citations

Rashba spin-orbit coupling in the square-lattice Hubbard model: A truncated-unity functional renormalization group study

Jacob Beyer, Jonas B. Profe, Lennart Klebl +5 more

The Rashba-Hubbard model on the square lattice is the paradigmatic case for studying the effect of spin-orbit coupling, which breaks spin and inversion symmetry, in a correlated electron system. We employ a truncated-unity variant of the functional renormalization group which allows us to analyze magnetic and superconducting instabilities on equal footing. We derive phase diagrams depending on the strengths of Rasbha spin-orbit coupling, real second-neighbor hopping, and electron filling. We find commensurate and incommensurate magnetic phases which compete with $d$-wave superconductivity. Due to the breaking of inversion symmetry, singlet and triplet components mix; we quantify the mixing of $d$-wave singlet pairing with $f$-wave triplet pairing.

arXiv:2210.09384•Physical review. B./Physical review. B•Mar 7, 2023•23 citations

Repulsive atomic Fermi gas with Rashba spin-orbit coupling: A quantum Monte Carlo study

Alberto Ambrosetti, Pier Luigi Silvestrelli, Francesco Pederiva +2 more

Thanks to the recent experimental realization and control of artificial gauge fields, spin-orbit (SO) couplings are witnessing an ever increasing interest in the field of cold atoms. However, predicting their effect on spin polarization and energetic properties of interacting systems is a major challenge, due to the complex interplay between spin and position dynamics. In this work we exploit the diffusion Monte Carlo algorithm to compute energetic and polarization properties of a three-dimensional repulsive Fermi gas in the presence of Rashba spin-orbit coupling. We find that SO effects tend to contrast the spin alignment induced by the exchange interaction, slightly shifting the onset of the Stoner instability towards larger values of the scattering length. In addition, polarization and energy properties of the system can be tuned trough a combined control of the repulsive interaction and Rashba coupling.

Physical Review A•May 26, 2015•8 citations

Rashba versus Kohn-Luttinger: Evolution of p -wave superconductivity in magnetized two-dimensional Fermi gases subject to spin-orbit interactions

Ethan Lake, Caleb Webb, D. A. Pesin +1 more

We study how the Rashba spin-orbit interaction influences unconventional superconductivity in a two-dimensional electron gas partially spin polarized by a magnetic field. Somewhat surprisingly, we find that for all field orientations, only the larger Fermi surface is superconducting. When the magnetic field is oriented out of plane, the system realizes a topological $p+ip$ pairing state. When the field is rotated in plane, the order parameter develops nodes along the field direction and finite center-of-mass-momentum pairing is realized. We demonstrate that the pairing symmetry of the system can be easily probed experimentally due to the dependence of various thermodynamic quantities on the magnetic field geometry, and calculate the electronic specific heat as an example.

arXiv:1602.02741•Physical review. B./Physical review. B•Jun 24, 2016•11 citations

Itinerant chiral ferromagnetism in a trapped Rashba spin-orbit-coupled Fermi gas

Shang-Shun Zhang, Wu-Ming Liu, Han Pu

We consider a repulsive two-component Fermi gas confined in a two-dimensional isotropic harmonic potential and subject to a large Rashba spin-orbit coupling. The single-particle dispersion can be tailored by the spin-orbit-coupling term, which provides an opportunity to study itinerant ferromagnetism in this system. We show that the interplay among spin-orbit coupling, correlation effect, and mean-field repulsion leads to a competition between ferromagnetic and nonmagnetic phases. The weakly correlated nonmagnetic and the ferromagnetic phases can be well described by the mean-field Hartree-Fock theory, while the transition between the ferromagnetic and a strongly correlated nonmagnetic phase is driven by beyond-mean-field quantum correlation effect. Furthermore, the ferromagnetic phase of this system possesses a chiral current density induced by the Rashba spin-orbit coupling, whose experimental signature is investigated.

arXiv:1509.04095•Physical Review A•Apr 4, 2016•7 citations
We study a model of a two-dimensional repulsive Fermi gas with Rashba spin-orbit coupling \ensuremathαR{\ensuremath{\alpha}}_{R}\ensuremathαR​ and investigate the superconducting instability using the renormalization-group approach. We find that, in general, superconductivity is enhanced as the dimensionless ratio 12m\ensuremathαR2/EF\frac{1}{2}m{\ensuremath{\alpha}}_{R}^{2}/{E}_{F}21​m\ensuremathαR2​/EF​ increases, resulting in unconventional superconducting states which break time-reversal symmetry.
We study the superconducting instability and the resulting superconducting states in a two-dimensional repulsive Fermi gas with Rashba spin–orbit coupling at low electron density (namely the Fermi energy E F is lower than the energy E R of the Dirac point induced by Rashba coupling). We find that superconductivity is enhanced as the dimensionless Fermi energy ( ) decreases, due to two reasons. First, the density of states at increases as . Second, the particle–hole bubble becomes more anisotropic, resulting in an increasing effective attraction. The superconducting state is always in the total angular momentum (or ) channel with Chern number C = 4 (or ), breaking time reversal symmetry spontaneously. Although a putative Leggett mode is expected due to the two-gap nature of the superconductivity, we find that it is always damped. More importantly, once a sufficiently large Zeeman coupling is applied to the superconducting state, the Chern number can be tuned to be ±1 and Majorana zero modes exist in the vortex cores.
Motivated by the remarkable experimental control of synthetic gauge fields in ultracold atomic systems, we investigate the effect of an artificial Rashba spin-orbit coupling on the spin polarization of a two-dimensional repulsive Fermi gas. By using a variational many-body wave function, based on a suitable spinorial structure, we find that the polarization properties of the system are indeed controlled by the interplay between spin-orbit coupling and repulsive interaction. In particular, two main effects are found: (1) The Rashba coupling determines a gradual increase of the degree of polarization beyond the critical repulsive interaction strength, at variance with conventional two-dimensional Stoner instability. (2) The critical interaction strength, above which finite polarization is developed, shows a dependence on the Rashba coupling, i.e., it is enhanced in case the Rashba coupling exceeds a critical value. A simple analytic expression for the critical interaction strength is further derived in the context of our variational formulation, which allows for a straightforward and insightful analysis of the present problem.
The Rashba-Hubbard model on the square lattice is the paradigmatic case for studying the effect of spin-orbit coupling, which breaks spin and inversion symmetry, in a correlated electron system. We employ a truncated-unity variant of the functional renormalization group which allows us to analyze magnetic and superconducting instabilities on equal footing. We derive phase diagrams depending on the strengths of Rasbha spin-orbit coupling, real second-neighbor hopping, and electron filling. We find commensurate and incommensurate magnetic phases which compete with ddd-wave superconductivity. Due to the breaking of inversion symmetry, singlet and triplet components mix; we quantify the mixing of ddd-wave singlet pairing with fff-wave triplet pairing.
Thanks to the recent experimental realization and control of artificial gauge fields, spin-orbit (SO) couplings are witnessing an ever increasing interest in the field of cold atoms. However, predicting their effect on spin polarization and energetic properties of interacting systems is a major challenge, due to the complex interplay between spin and position dynamics. In this work we exploit the diffusion Monte Carlo algorithm to compute energetic and polarization properties of a three-dimensional repulsive Fermi gas in the presence of Rashba spin-orbit coupling. We find that SO effects tend to contrast the spin alignment induced by the exchange interaction, slightly shifting the onset of the Stoner instability towards larger values of the scattering length. In addition, polarization and energy properties of the system can be tuned trough a combined control of the repulsive interaction and Rashba coupling.
We study how the Rashba spin-orbit interaction influences unconventional superconductivity in a two-dimensional electron gas partially spin polarized by a magnetic field. Somewhat surprisingly, we find that for all field orientations, only the larger Fermi surface is superconducting. When the magnetic field is oriented out of plane, the system realizes a topological p+ipp+ipp+ip pairing state. When the field is rotated in plane, the order parameter develops nodes along the field direction and finite center-of-mass-momentum pairing is realized. We demonstrate that the pairing symmetry of the system can be easily probed experimentally due to the dependence of various thermodynamic quantities on the magnetic field geometry, and calculate the electronic specific heat as an example.
We consider a repulsive two-component Fermi gas confined in a two-dimensional isotropic harmonic potential and subject to a large Rashba spin-orbit coupling. The single-particle dispersion can be tailored by the spin-orbit-coupling term, which provides an opportunity to study itinerant ferromagnetism in this system. We show that the interplay among spin-orbit coupling, correlation effect, and mean-field repulsion leads to a competition between ferromagnetic and nonmagnetic phases. The weakly correlated nonmagnetic and the ferromagnetic phases can be well described by the mean-field Hartree-Fock theory, while the transition between the ferromagnetic and a strongly correlated nonmagnetic phase is driven by beyond-mean-field quantum correlation effect. Furthermore, the ferromagnetic phase of this system possesses a chiral current density induced by the Rashba spin-orbit coupling, whose experimental signature is investigated.