Representative longitudinal optical phonon modes in polar semiconductor quantum dots

Existence of representative longitudinal optical (LO) phonon modes is theoretically discussed for the case of polar semiconductor cylindrical quantum dots embedded in a semiconductor matrix. The approach is developed within the dielectric continuum model considering the Fr\"ohlich interaction between electrons and the confined LO phonons. The theory is applied to cylindrical GaAs/AlAs quantum dots within an adiabatic treatment.Comment: 8 pages, 1 figur

Cheche Pelcher to Dear Fred, 10 November 1871

https://egrove.olemiss.edu/bernard/1048/thumbnail.jp

Interplay of the Rashba and Dresselhaus spin-orbit coupling in the optical spin susceptibility of 2D electron systems

We present calculations of the frequency-dependent spin susceptibility tensor of a two-dimensional electron gas with competing Rashba and Dresselhaus spin-orbit interaction. It is shown that the interplay between both types of spin-orbit coupling gives rise to an anisotropic spectral behavior of the spin density response function which is significantly different from that of vanishing Rashba or Dresselhaus case. Strong resonances are developed in the spin susceptibility as a consequence of the angular anisotropy of the energy spin-splitting. This characteristic optical modulable response may be useful to experimentally probe spin accumulation and spin density currents in such systems

Optical Excitations of Colloidal Core/Shell Semiconductor Quantum Dots

The energy structure of multi‐layer core/shell semiconductor quantum dots (QDs) is simulated and the optical absorption is described within the linear response theory. The lattice‐mismatch strain field of the multi‐layer nanostructures of spherical symmetry is modelled by a linear continuum elasticity treatment. The excitonic effect is estimated by a configuration interaction approach. Multi‐layer core/shell QDs of II‐VI semiconductors with heterostructures of type I and II are discussed. Localization of the photo-excited carriers induced by coating explains the optical stability of these multi‐layer nanostructures