Department of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA, United Kingdom.
Phys Rev Lett. 2012 Nov 2;109(18):187402. doi: 10.1103/PhysRevLett.109.187402. Epub 2012 Oct 31.
Under optical excitation, coupled quantum wells are known to reveal fascinating features in the photoluminescence pattern originating from dipole orientated indirect excitons. The appearance of an external ring has been attributed to macroscopic charge separation in the quantum well plane. We present a classical model of nonlinear diffusion to account for the observed fragmentation of the external ring into a periodic array of islands. The model incorporates the Coulomb interactions between electrons, holes, and indirect excitons. At low temperatures, these interactions lead to pattern formation similar to the experimentally observed ring fragmentation. The fragmentation is found to persist to temperatures above the quantum degeneracy temperature of indirect excitons.
在光激发下，耦合量子阱在源于偶极定向间接激子的光致发光模式中表现出迷人的特征。外部环的出现归因于量子阱平面中的宏观电荷分离。我们提出了一个非线性扩散的经典模型，以解释观察到的外部环分裂成周期性的岛阵列。该模型包含了电子、空穴和间接激子之间的库仑相互作用。在低温下，这些相互作用导致与实验观察到的环分裂相似的模式形成。发现这种分裂一直持续到高于间接激子量子简并温度的温度。
