Atomi stic Simulation ofNon-Degeneracy andOptical Polarization Anisotropy inPyramidal Quantum Dots

Self-assembled quantumdots(QDs)realized by Stranski-Krastanov growthmodeoftendemonstrate polarized transitions inquantized electron (hole) states andnon-degeneracy inthefirst exicted state invarious spectroscopic analyses. These observations confirm thepresence ofcertain symmetrybreak- ing/lowering mechanisms intheselowdimensional QDs which cannot berepresented accurately withcontinuum material repre- sentations. Atomistic calculations indeed reveal optical polariza- tionanisotropy andnon-degeneracy intheexcited states dueto underlying crystalline symmetry, atomistic long-range strain and piezoelectric fields. Thisworkpresents theuseofthecom- prehensive atomistic simulation package NEMO 3-Dinthestudy ofcompeting effects inrealistically-sized pyramidal InAs/GaAs quantumdots. IndexTerms-Quantum dots, Atomistic strain, Optical polari- zation, Piezoelectricity, Crystal symmetry.