Observation of preformed electron-hole Cooper pairs in highly excited ZnO

Versteegh, Marijn A. M.; Lange, A. J. van; Stoof, H. T. C.; Dijkhuis, J. I.

doi:10.1103/physrevb.85.195206

Cited by 20 publications

(24 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It was successful in explaining the light reflection from macroscopic crystals of ZnO at room temperature at various excitation intensities [18], as well as stimulated emission from preformed electron-hole Cooper pairs at cryogenic temperatures [19]. Using our theory, we calculated that the Mott density in ZnO equals 1:5 Â 10 24 m À3 at T ¼ 300 K, and we argued that this is a more accurate result than was obtained by others.…”

supporting

confidence: 52%

Room-Temperature Laser Emission of ZnO Nanowires Explained by Many-Body Theory

2012

Self Cite

View full text Add to dashboard Cite

Are excitons involved in lasing in ZnO nanowires or not? Our recently developed and experimentally tested quantum many-body theory sheds new light on this question. We measured the laser thresholds and Fabry-Pérot laser modes for three radically different excitation schemes. The thresholds, photon energies, and mode spacings can all be explained by our theory, without invoking enhanced light-matter interaction, as is needed in an earlier excitonic model. Our conclusion is that lasing in ZnO nanowires at room temperature is not of excitonic nature, as is often thought, but instead is electron-hole plasma lasing.

show abstract

supporting

confidence: 52%

Room-Temperature Laser Emission of ZnO Nanowires Explained by Many-Body Theory

2012

Self Cite

View full text Add to dashboard Cite

show abstract

“…On the other hand, at equilibrium without photons, there are several predicted phenomena 2 3 4 5 6 when the electron–hole (e–h) internal structure is taken into account. One example is the e–h Bardeen–Cooper–Schrieffer (BCS) phase in the high e–h density regime 2 7 , where the condensation of e–h Cooper pairs opens a gap around the Fermi energy in the electron and hole energy dispersions. Since such BCS physics is based on assumptions of equilibrium in e–h systems, with the complete lack of photons, it has been traditionally conceptually disconnected from semiconductor lasers (e-h-p system).…”

mentioning

confidence: 99%

High-energy side-peak emission of exciton-polariton condensates in high density regime

Horikiri

Yamaguchi

Kamide

et al. 2016

Sci Rep

View full text Add to dashboard Cite

In a standard semiconductor laser, electrons and holes recombine via stimulated emission to emit coherent light, in a process that is far from thermal equilibrium. Exciton-polariton condensates–sharing the same basic device structure as a semiconductor laser, consisting of quantum wells coupled to a microcavity–have been investigated primarily at densities far below the Mott density for signatures of Bose-Einstein condensation. At high densities approaching the Mott density, exciton-polariton condensates are generally thought to revert to a standard semiconductor laser, with the loss of strong coupling. Here, we report the observation of a photoluminescence sideband at high densities that cannot be accounted for by conventional semiconductor lasing. This also differs from an upper-polariton peak by the observation of the excitation power dependence in the peak-energy separation. Our interpretation as a persistent coherent electron-hole-photon coupling captures several features of this sideband, although a complete understanding of the experimental data is lacking. A full understanding of the observations should lead to a development in non-equilibrium many-body physics.

show abstract

“…Since the condensation of hetero pairs is also discussed in, for example, an exciton gas [59][60][61][62][63], an exciton-polariton gas [64][65][66][67], as well as a dense quark matter [68,69], the realization of a superfluid 6 Li-40 K Fermi gas would give great impact on these fields.…”

Section: Introductionmentioning

confidence: 99%

Heteropairing and component-dependent pseudogap phenomena in an ultracold Fermi gas with different species with different masses

Hanai

Ōhashi

2014

Phys. Rev. A

View full text Add to dashboard Cite

We investigate the superfluid phase transition and single-particle excitations in the BCS (BareenCooper-Schrieffer)-BEC (Bose-Einstein condensation) crossover regime of an ultracold Fermi gas with mass imbalance. In our recent paper [R. Hanai, et. al., Phys. Rev. A 88, 053621 (2013)we showed that an extended T -matrix approximation (ETMA) can overcome the serious problem known in the ordinary (non-self-consistent) T -matrix approximation that it unphysically gives double-valued superfluid phase transition temperature T c in the presence of mass imbalance. However, at the same time, the ETMA was also found to give the vanishing T c in the weak-coupling and highly mass-imbalanced case. In this paper, we inspect the correctness of this ETMA result, using the self-consistent T -matrix approximation (SCTMA). We show that the vanishing T c is an artifact of the ETMA, coming from an internal inconsistency of this theory. The superfluid phase transition actually always occurs, irrespective of the ratio of mass imbalance. We also apply the SCTMA to the pseudogap problem in a mass-imbalanced Fermi gas. We show that pairing fluctuations induce different pseudogap phenomena between the the light component and heavy component. We also point out that a 6 Li-40 K mixture is a useful system for the realization of a hetero pairing state, as well as for the study of component-dependent pseudogap phenomena.

show abstract

Observation of preformed electron-hole Cooper pairs in highly excited ZnO

Cited by 20 publications

References 66 publications

Room-Temperature Laser Emission of ZnO Nanowires Explained by Many-Body Theory

Room-Temperature Laser Emission of ZnO Nanowires Explained by Many-Body Theory

High-energy side-peak emission of exciton-polariton condensates in high density regime

Heteropairing and component-dependent pseudogap phenomena in an ultracold Fermi gas with different species with different masses

Contact Info

Product

Resources

About