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arXiv · 1111.4336

Observation of Preformed Electron-Hole Cooper Pairs

Marijn A. M. Versteegh·A. J. van Lange·H. T. C. Stoof·Jaap I. Dijkhuis
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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.

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Marijn A. M. Versteegh, A. J. van Lange, H. T. C. Stoof, Jaap I. Dijkhuis. 2011-11-18. Observation of Preformed Electron-Hole Cooper Pairs. https://doi.org/10.1103/physrevb.85.195206

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