Session I8 - Computational Nanostructures.
INVITED session, Tuesday afternoon, March 21
101H, MCC

15:05
I8.02 Electron Correlation in Quantum Dots using Quantum Monte Carlo
John Shumway (National Renewable Energy Laboratory, Golden, Colorado 80401)

Self-assembled, Stranski-Krastanow (SK) grown InAs/GaAs quantum dots are able to hold multiple localized electrons and holes, which interact via Coulomb interaction and Pauli exclusion. These interactions affect measurable quantities, such as the binding energy of excitons and biexcitons, electron addition energies, and charge distributions. Theoretical methods for predicting these properties may be classified by how they model the single particle states and the treatment of interactions. Popular models include: (1) single band effective mass (2) multiple band k\cdot p, and (3) empirical psuedopotential atomistic models. The effects of interactions may be separated into mean field effects and many-body correlation effects. Correlation effects have been approximated using techniques such as density functional theory (DFT) and configuration interaction (CI). An alternative approach is to use quantum Monte Carlo (QMC) methods, which stochastically sample the exact properties of many-body states. We give an overview of our application of QMC methods to SK dots within the single band effective mass description. We compare our results to single band DFT calculations of electron addition energies, and to many-band pseudopotential CI calculations of exciton binding energies. We discuss the benefits and limitations of the QMC methods and areas for future development.