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Unconventional superconductivity in a two-dimensional repulsive gas of fermions with spin–orbit coupling

Luyang Wang, Oskar Vafek

arXiv:1307.7953Physica C SuperconductivityOct 23, 201314 citations

Superconductivity in a low-density two-band model with a repulsive interaction: extended analysis

М. А. Баранов, M. Yu. Kagan, Daniel R. Parsons

Journal of Experimental and Theoretical PhysicsJul 1, 19923 citations

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.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:1612.06613Journal of Physics CommunicationsSep 1, 20172 citations

Superconductivity from purely repulsive interactions in the 2D electron gas

S. Raghu, Steven Allan Kivelson

Bulletin of the American Physical SocietyMar 24, 20110 citations

Superconductivity in Repulsive Fermi-Systems at Low Density

M. Yu. Kagan, Dmitri V. Efremov, M. S. Mar’enko +1 more

arXiv:1111.3230Journal of Superconductivity and Novel MagnetismJun 12, 20132 citations

Superfluid-insulator transition and the BEC-BCS crossover in the Rashba moat band

Hassan Allami, O. A. Starykh, D. A. Pesin

We study the superconducting transition in a two-dimensional electron gas with strong Rashba spin-orbit coupling. We assume low electron density, such that only the majority spin band participates in the transition. We show that the superconducting transition follows either the Bose-Einstein condensation (BEC), or the Bardeen-Cooper-Schrieffer (BCS) scenarios, depending on the position of the chemical potential with respect to the bottom of the majority band, and the strength of the Coulomb repulsion between electrons. Hence, the BEC-BCS crossover in this system can be driven either by the change in the chemical potential, or the distance to a gate.We study the superconducting transition in a two-dimensional electron gas with strong Rashba spin-orbit coupling. We assume low electron density, such that only the majority spin band participates in the transition. We show that the superconducting transition follows either the Bose-Einstein condensation (BEC), or the Bardeen-Cooper-Schrieffer (BCS) scenarios, depending on the position of the chemical potential with respect to the bottom of the majority band, and the strength of the Coulomb repulsion between electrons. Hence, the BEC-BCS crossover in this system can be driven either by the change in the chemical potential, or the distance to a gate.

arXiv:1812.06998Physical review. B./Physical review. BMar 7, 20192 citations

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

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