Spatial and fine energy structure of indirect exciton

Abstract

Quantum states of a spatially indirect exciton (IX), including its binding energy, are largely determined by the geometry of the spatial quantum structure consisting of (IX) and the interface (IXI). Unfortunately, this fact has been poorly studied both experimentally and theoretically. In this paper, the parameters of the IXI geometry and their effect on the IX binding energy spectrum are analytically investigated for the first time. For this purpose, the potential of the Coulomb interaction of an electron and a hole is determined using the image method. It is shown that the geometry parameters are quantized, and the effective permittivity of the interface becomes dependent on the orbital and magnetic quantum numbers of IX. A nonlinear dependence of the IX binding energy on the geometric parameters is observed. All these manifestations of the geometry are accessible to experimental observation. Each geometry has its own quantum states. This opens up the possibility of using IXI in exciton spectroscopy of the interface layer. The controllability of the IXI geometry by polarized light allows us to hope for using quantum geometric states of IX as qubits. In this work, various geometric states IX of two planar heterostructures SiO₂/Si₃N₄ and GaAs/CdSe were modeled as an example.

Graphical abstract