On the anomalous Stark effect in a thin disc-shaped quantum dot

J Phys Condens Matter. 2010 Sep 22;22(37):375301. doi: 10.1088/0953-8984/22/37/375301. Epub 2010 Aug 25.

Abstract

The effect of a lateral external electric field F on an exciton ground state in an InAs disc-shaped quantum dot has been studied using a variational method within the effective mass approximation. We consider that the radial dimension of the disc is very large compared to its height. This situation leads to separating the excitonic Hamiltonian into two independent parts: the lateral confinement which corresponds to a two-dimensional harmonic oscillator and an infinite square well in the growth direction. Our calculations show that the complete description of the lateral Stark shift requires both the linear and quadratic terms in F which explains that the exciton possess nonzero lateral dipolar moment and polarizability. The fit of the calculated Stark shift permits us to estimate the lateral permanent dipole moment and the polarizability according to the disc size. Our results are compared to those existing in the literature. In addition the behavior of the optical integral shows that the exciton lifetime is greater than that under zero field which is due to the field-induced polarization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arsenicals / chemistry*
  • Electromagnetic Fields
  • Indium / chemistry*
  • Models, Chemical*
  • Nanostructures / chemistry*
  • Nanostructures / ultrastructure*
  • Particle Size
  • Quantum Dots*
  • Quantum Theory

Substances

  • Arsenicals
  • Indium
  • indium arsenide