Observation of Preformed Electron-Hole Cooper Pairs

Abstract

Electrons and holes in a semiconductor form hydrogen-atom-like bound states, called excitons. At high electron-hole densities the attractive Coulomb force becomes screened and excitons can no longer exist. Bardeen-Cooper-Schrieffer theory predicts that at such high densities co-operative many-body effects can at low temperatures induce a bound state, an electron-hole Cooper pair, comparable to an electron-electron Cooper pair in a superconductor. Here we report the first observation of preformed electron-hole Cooper pairs in a semiconductor. By measuring stimulated emission from a dense electron-hole gas in ZnO, we have explored both the crossover from the electron-hole plasma to the preformed Cooper-pair regime, and the crossover from the exciton to the preformed Cooper-pair regime.

Main article: 11 pages, 3 figures. Supplement: 10 pages, 4 figures

References in corpus (10)

• Vortices and Superfluidity in a Strongly Interacting Fermi Gas
• Observation of the Pairing Gap in a Strongly Interacting Fermi Gas
• Spontaneous Coherence in a Cold Exciton Gas
• Observation of pseudogap behavior in a strongly interacting Fermi gas
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• Polarons in Extremely Polarized Fermi Gases: The Strongly Interacting 6Li-40K Mixture

Cited by in corpus (6)

• Ultrafast dynamics of hot charge carriers in an oxide semiconductor probed by femtosecond spectroscopic ellipsometry
• Excitonic Gap Formation in Pumped Dirac Materials
• High-energy side-peak emission of exciton-polariton condensates in high density regime
• Generating Functional Approach for Spontaneous Coherence in Semiconductor Electron-Hole-Photon Systems
• Hetero pairing and component-dependent pseudogap phenomena in an ultracold Fermi gas with mass imbalance
• Prolonged photo-carriers generated in a massive-and-anisotropic Dirac material