Bose–Einstein condensation of excitons in Cu₂O: progress over 30 years

Abstract

Experiments on Bose-Einstein condensation (BEC) of excitons in the semiconductor Cu2O started over 30 years ago, as one of the first serious attempts at exciton BEC. Early claims were based on spectroscopic signatures and transport data which have since been reinterpreted, in large part because the Auger recombination process for excitons was not well understood. Understanding of the Auger process has advanced, and recent experiments have made significant progress toward exciton BEC. We review the history of experiments on exciton BEC in Cu2O, the Auger recombination process, and the prospects for observing exciton BEC in this system in the near future.

Bose-Einstein Condensation of Excitons in Planar Systems and Superconductive Phase Transition Temperature

“…In Section 2, we analyzed the general distribution function for boson particles given by (2)(3)(4)(5). We notice that for such distribution of excitons in planar systems, the chemical potential μ depends on the surface density of the excitons.…”

“…Analyses of BEC of excitons in Cu 2 O [2], in potential traps [3], and for exciton-polaritons [4] have been reported. BEC excitonic effects have been described in some review articles [5][6][7]. A book about BEC of excitons and bi-excitons has been published [8].…”

“…The special structures for indirect excitons [11][12][13] enable the control of various parameters for the excitonic systems. For high density of excitons in planar, or semiplanar, systems, the observation of BEC of excitons can be related to coherent luminescence from all the excitons included in a coherent area [1][2][3][4][5][6][7][8][9][10][11][12][13][14].…”

Magneto-absorption spectra of hydrogen-like yellow exciton series in cuprous oxide: excitons in strong magnetic fields

“…The corrections to the binding energy of the higher levels, produced by these mechanisms, are negligible. The revival of interest in Cu 2 O was motivated by the search for the Bose-Einstein condensation of the exciton gas 4–8 and rapid developments of ab-initio methods 9 , e.g. GW and Bethe-Salpeter calculations, for which Cu 2 O serves as an important benchmark system.…”

Theory of zero‐phonon decay luminescence of semiconductor excitons

“…At present, cuprous oxide (Cu 2 O) is in the focus of both experimental and theoretical efforts (for a recent overview see Ref. ), namely because of the large binding energy and the long lifetime of the exciton states in this material. In current experiments, entrapment of the excitons in a strain induced external potential is used to obtain sufficiently high particle densities.…”