Theory of exciton fine structure in semiconductor quantum dots: quantum dot anisotropy and lateral electric field

TL;DR

This paper develops a theoretical model for exciton fine structure in semiconductor quantum dots, analyzing how anisotropy and lateral electric fields influence excitonic energy levels and splitting.

Contribution

It derives an effective exciton Hamiltonian including long-range exchange interactions within the k*p effective mass approximation, explicitly expressing exchange matrix elements.

Findings

Bright exciton splitting depends on quantum dot shape and electric field.

Anisotropy and electric field significantly alter exciton energy levels.

Model provides insights into exciton behavior in anisotropic quantum dots.

Abstract

Theory of exciton fine structure in semiconductor quantum dots and its dependence on quantum dot anisotropy and external lateral electric field is presented. The effective exciton Hamiltonian including long range electron-hole exchange interaction is derived within the k*p effective mass approximation (EMA). The exchange matrix elements of the Hamiltonian are expressed explicitly in terms of electron and hole envelope functions. The matrix element responsible for the "bright" exciton splitting is identified and analyzed. An excitonic fine structure for a model quantum dot with quasi- two-dimensional anisotropic harmonic oscillator (2DLAHO) confining potential is analyzed as a function of the shape anisotropy, size and applied lateral electric field.