耦合量子阱中激子凝聚研究新进展

New progress of exciton condensation in coupled quantum wells

玻色-爱因斯坦凝聚成为探索量子世界的一种新方法,而且在半导体纳米结构中激子的凝聚研究取得了很大进展。实验上利用耦合量子阱间接激子中电子和空穴在空间上的分离,显著提高了激子的冷却速度和寿命,成功地把激子冷却到1K以下,观察到了激子的准凝聚状态。着重介绍冷激子系统凝聚现象、发光图案和宏观有序的激子态。理解这些简并激子系统的形成机理,为其在半导体纳米结构中最终实现玻色-爱斯坦凝聚提供新的机会。

The possible way offered by Bose-Einstein condensation for investigating the quantum world made much progress for exciton condensation in semiconductor nanometer structures. In particular, the lifetime of indirect excitons has been dramatically improved by more than two orders of magnitudes by using the spatial separation of electrons and holes that form excitons in coupled quantum wells. This allows the excitons to be cooled down below 1 K and the condensation or highly degenerate states of excitons to be realized experimentally. Phenomena in the cold exciton gases such as condensation, pattern formation and macroscopically ordered exciton states were reviewed. Understanding the formation mechanisms of these degenerate exciton systems can open new opportunities for the last realization of exciton Bose-Einstein condensation in semiconductor nanometer structures.