145 research outputs found
Interplay of Phonon and Exciton-Mediated Superconductivity in Hybrid Semiconductor-Superconductor Structures
We predict a strong enhancement of the critical temperature in a conventional
Bardeen-Cooper-Schrieffer (BCS) superconductor in the presence of a bosonic
condensate of exciton-polaritons. The effect depends strongly on the ratio of
the cutoff frequencies for phonon and exciton-polariton mediated BCS
superconductivity, respectively. We also discuss a possible design of hybrid
semiconductor-superconductor structures suitable for the experimental
observation of such an effect.Comment: 5 pages, 3 figures, accepted in Phys. Rev. Let
Symmetry breaking and superfluid currents in a split-ring spinor polariton condensate
Bosonic condensates of spin-less non-interacting particles confined on a ring
cannot propagate circular periodic currents once rotation symmetry of the
system is broken. However a persistent current may appear due to inter-particle
interactions exceeding some critical strength. In this up-critical regime
breaking of the symmetry between the clockwise and anticlockwise rotations
takes place. We consider this symmetry-breaking scenario in the case of a
spinor condensate of exciton polaritons trapped on a ring split by a potential
barrier. Due to the intrinsic symmetry of the effective spin-orbit interaction
which stems from the linear splitting between transverse-electric and
transverse-magnetic microcavity modes, the potential barrier blocks the
circulating current and imposes linear polarization patterns. On the other
hand, circularly polarized polaritons form circular currents propagating in
opposite directions with equal absolute values of angular momentum. In the
presence of inter-particle interactions, the symmetry of clockwise and
anticlockwise currents can be broken spontaneously. We describe several
symmetry-breaking scenarios which imply either restoration of the global
condensate rotation or the onset of the circular polarization in the
symmetry-broken state.Comment: 9 pages, 5 figure
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