Collective states of excitons in semiconductors

Leonid V. Keldysh, Andrey Nikolaevich Kozlov

Victor I. Klimov

Lebedev, Mikhail, A.L. Parakhonsky, A. A. Demenev

Semiconductor microcavities are widely used to study collective interactions of cavity exciton-polaritons leading to their condensation phenomenon. Exciton-light interaction is highly enhanced in such structures due to the resonance enhancement of the electromagnetic field inside the high quality cavity. Considerably lower interest is concerned to exciton states non-resonant with the cavity mode for which the exciton-photon interaction is strongly reduced due to the existence of the cavity. We point out here that these states are responsible for non-classical light generation in semiconductor microcavities.

H. K. Avetissian, A. K. Avetissian, G. F. Mkrtchian +1 more

The collective decay of excitons from initial Bose-Einstein condensate state is investigated theoretically. As a practically more interesting case we consider excitons of the yellow series in the semiconductor cuprous oxide where we have collective photon and phonon-assisted decay of excitons. It is shown that because of intrinsic instability of recoilless two-boson decay of Bose-Einstein condensate, the spontaneously emitted bosonic pairs are amplified, leading to an exponential buildup of a macroscopic population into the certain modes. The collective decay rate has a nonlinear dependence on the excitonic density being comparable or larger than the Auger recombination loss rate up to the high densities, which makes obtainable its observation. The phenomenon considered can also be applied for the realization of a phonon laser.

Leonid V. Keldysh

Leonid V. Keldysh