Magneto-optical response of CdSe nanostructures

Abstract

We present theoretical calculations of the Landé g-factors of semiconductor nanostructures using a time-dependent empirical tight-binding method. The eigenenergies and eigenfunctions of the band edge states are calculated as a function of an external magnetic field with the electromagnetic field incorporated into the tight-binding Hamiltonian in a gauge-invariant form. The spin-orbit interaction and magnetic field are treated non-perturbatively. The g-factors are extracted from the energy splitting of the eigenstates induced by the applied magnetic field. Both electron and hole g-factors are investigated for CdSe nanostructures. The size and aspect ratio dependence of g-factors is studied. We observe that the electron g-factors are anisotropic and find that the calculated values agree quantitatively with experimental data. We conclude that the two distinct g-factor values extracted from time resolved Faraday rotation experiments should be assigned to the anisotropic in plane ($g_{\parallel }$) and out of plane ($g_z$) electron g-factors, rather than to isotropic electron and exciton g-factors. We find that the anisotropy in the electron g-factor depends on the aspect ratio of the nanocrystal. The g-factor anisotropy derived from the wurtzite structure and from the non-unity aspect ratio may cancel each other in some regime. We observe that hole g-factors oscillate as a function of size, due to size dependent mixing between the heavy hole-light hole components of the valence band edge states. Extension to the calculation of exciton g-factors is discussed.

arXiv commentSubmitted to Phys. Rev. B

References in corpus (4)

• Spin dynamics in semiconductor nanocrystals
• Effect of the Surface on the Electron Quantum Size Levels and Electron g-Factor in Spherical Semiconductor Nanocrystals
• Consequences of local gauge symmetry in empirical tight-binding theory
• Tight-binding g-Factor Calculations of CdSe Nanostructures

Cited by in corpus (13)

• Recipes for spin-based quantum computing
• Fine structure and size dependence of exciton and bi-exciton optical spectra in CdSe nanocrystals
• Anomalous circular polarization of magneto-photoluminescence from individual CdSe nanocrystals
• Spin dynamics in electrochemically charged CdSe quantum dots
• Spin-orbit coupling and crystal-field splitting in the electronic and optical properties of nitride quantum dots with a wurtzite crystal structure
• Spin dynamics and level structure of quantum-dot quantum wells
• Theory of highly excited semiconductor nanostructures including Auger coupling: exciton-bi-exciton mixing in CdSe nanocrystals
• Electromagnetic response of broken-symmetry nano-scale clusters
• Optical and electronic properties of colloidal CdSe Quantum Rings
• Quantum shape effects on Zeeman splittings in semiconductor nanostructures
• Atomistic Theory of Coherent Spin Transfer between Molecularly Bridged Quantum Dots
• Effective Landé factors of electrons and holes in lead chalcogenide nanocrystals
• Electron, hole and exciton effective g-factors in semiconductor nanocrystals