A model study of quantum dot polarizability calculations using time-dependent density functional methods

Abstract

We compare two time-dependent methods (time-dependent Hartree and time-dependent density functional methods) with a time-independent density functional method for the calculation of the frequency dependent polarizability and resulting absorption spectrum of two interacting quantum confined particles (quantum dots). The system is examined within the dipole approximation and the methods are evaluated in terms of the optical absorption spectrum. The spectral noise generated by time-dependent methods is a sensitive measure of the degree of broken correlation between the quantum degrees of freedom and the time-dependent density functional method may help to quantify the efficacy of correlation-exchange potentials that are used in density functional models. With respect to the quantum confinement issue, we find that increasing the interaction energy between nearest neighbor quantum dot sites represented in our model tends to shift absorption intensity to higher energy transitions.