Computational methods for studies of multiexciton complexes

Abstract

AbstractPowerful computational methods are presented for studies of energy levels, photon‐recombination rates, and phonon‐relaxation rates of neutral and charged multiexciton complexes at correlated levels of theory. The electron–hole system is described by a two‐band effective‐mass Hamiltonian. The one‐particle functions are expanded in a basis set consisting of anisotropic Gaussian functions. The many‐body Hamiltonian constructed in the space of the antisymmetric products of one‐particle functions is diagonalized using general coupled‐cluster and configuration‐interaction methods. The expansion coefficients of the coupled‐cluster and configuration‐interaction wave functions are obtained by solving the corresponding equations using direct iterative algorithms. We demonstrate the potential of the computational approaches by calculating total energies of multiexciton complexes at coupled‐cluster and configuration‐interaction levels. Computational methods for studies of radiative recombination and phonon‐relaxation rates have also been developed and results are reported for radiative recombination rates and recombination energies of the exciton, biexciton, and of the positive and the negative trions confined in a InGaAs/GaAs quantum‐dot sample. Phonon‐relaxation rates have been calculated for a few low‐lying Δ g states of the exciton complex of the same quantum‐dot sample. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)