Dresden 2003 – scientific programme
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HL: Halbleiterphysik
HL 35: Quantenpunkte und -dr
ähte: Optische Eigenschaften I
HL 35.1: Talk
Wednesday, March 26, 2003, 17:30–17:45, BEY/154
Tight-binding study of the strain effects on the electronic properties of InAs/GaAs quantum dots — •Roberto Santoprete1, Belita Koiller2, Rodrigo Capaz2, Peter Kratzer3, Quincy Liu4, and Matthias Scheffler3 — 1Universidade Federal do Rio de Janeiro (Brazil) and Fritz-Haber-Institut der Max-Planck-Gesellschaft (Germany) — 2Universidade Federal do Rio de Janeiro (Brazil) — 3Fritz-Haber-Institut der Max-Planck-Gesellschaft (Germany) — 4Hahn-Meitner-Institut (Germany)
We present an atomistic investigation of the strain effects on the electronic properties of quantum dots (QD’s) within the empirical s p3 s* tight-binding (TB) model with interactions up to 2nd nearest neighbors and spin-orbit coupling. Results for the model system of capped pyramid shaped InAs QD’s in GaAs, with supercells containing ∼ 105 atoms are presented and compared with previous empirical pseudopotential results; the good agreement found shows that TB is a competitive tool for a realistic treatment. The strain is incorporated through two different approaches : the continuum elasticity theory and the atomistic valence force field model, which are combined. The TB treatment allows for the effects of bond length and bond angle deviations from ideal InAs and GaAs zincblende structure to be selectively removed from the electronic calculation, giving quantitative information on the impact of strain effects on the bound state energies and on the electron and hole wave function confinement inside the dot. Effects of dot-dot coupling have also been examined to determine the relative weight of both strain field and wave function overlap.