Ordered structures of exciton condensed phases in the presence of an inhomogeneous potential

Abstract

A theory of the separation of a system of indirect excitons into a condensed and a gaseous phase with the formation of regular patterns of alternating phases in inhomogeneous external fields is developed. The model of spinodal decomposition of phase transitions, generalized for systems of unstable particles, is used. The theory is applied to the study of the non-uniform distribution of the exciton density in a double quantum well under a slot cut in a metallic electrode. It is shown that in a certain range of exciton generation rates a chain of light-emitting islands periodically localized along the slot is developed. With increasing width of the slot, the chain splits into two parallel chains shifted by a half period with respect to each other. By creating a biased external potential along the slot, the periodical pattern could be forced to move along the slot. The effect of the motion of the islands should manifest itself as time oscillations of the intensity of the light emitted from a fixed point.

Exciton density pattern formation in laser irradiated quantum wells under electrodes of various shapes

“…We use the phenomenological model of phase transitions generalized for particles of the finite lifetime for simulation of the exciton density profiles under electrodes of different shapes. This section provides only a brief description of the simulation method, a detailed description of the approach can be found, for example, in [25,30]. The timedependent distribution of the exciton density n satisfies the nonlinear equation: .…”

“…The explanation of the experimentally observed spatial structures in the exciton density distribution was given in the papers [21][22][23][24][25]. The theoretical approaches of these works are based on two major assumptions: 1) there exists an exciton condensed phase caused by an attractive interaction between excitons; 2) the finite value of the exciton lifetime plays an important role in the formation of the exciton condensed phase.…”

“…The exciton density distribution is described phenomenologically using Landau model of phase transitions generalized for particles with the finite lifetime. This approach is based on two main assumptions used in our previous papers [21][22][23][24][25]30,31] that were successful in the explanation of experimental results.…”

Pulses of the Excitonic Condensed Phase in Semiconductors with Double Quantum Well at Steady Pumping

“…The explanation of the fragmentation of the inner ring in a laser sport observed in [25] was given in [26]. The developed theory allows one to predict the appearance of solitons [27], which present the localized regions of the exciton condensed phase, the movement of solitons in external fields [28,29], the generation of autowaves in the exciton condensed phases (solitons) at a steady state irradiation of double quantum wells, and the movement of the autowaves on macroscopic distances [30]. According to [27], several conditions should be realized for the appearance of the generation.…”

Amplification and passing through the barrier of the exciton condensed phase pulse in double quantum wells

“…In this work we study the formation, amplification and passing through the barrier of the exciton condensed phase pulse in the semiconductor double quantum well in the system, in which one of the electrodes has a slot, which creates an additional field to uniform field for excitons. The formation of the exciton condensed phase in the double quantum well under the slot excited by a steadystate uniform irradiation was studied in [19]. The approach used to describe the distribution of the exciton density in double quantum wells is based on the assumption of the exciton condensed phase existence due to the attraction between indirect excitons at some distances and the finite value of the exciton lifetime.…”