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

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

doi:10.1103/PhysRevB.85.195206

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

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

DOI 10.1103/PhysRevB.85.195206 · Physical Review B

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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. BCS theory predicts that at such high densities cooperative 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 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.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
ZnO Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown