gfactors and diamagnetic coefficients of electrons, holes, and excitons in InAs/InP quantum dots

Abstract

The electron, hole, and exciton g factors and diamagnetic coefficients have been calculated using envelopefunction theory for cylindrical InAs/InP quantum dots in the presence of a magnetic field parallel to the dot symmetry axis. A clear connection is established between the electron g factor and the amplitude of those valence-state envelope functions that possess nonzero orbital momentum associated with the envelope function. The dependence of the exciton diamagnetic coefficients on the quantum dot height is found to correlate with the energy dependence of the effective mass. Calculated exciton g factor and diamagnetic coefficients, constructed from the values associated with the electron and hole constituents of the exciton, match experimental data well, however including the Coulomb interaction between the electron and hole states improves the agreement. Remote-band contributions to the valence-band electronic structure, included perturbatively, reduce the agreement between theory and experiment.

Strain-inducedg-factor tuning in single InGaAs/GaAs quantum dots

“…The g tensor depends on the exact electronic structure of the QD and therefore also has a strong dependency on the size and shape of quantum dots [6][7][8]. This implies that the g tensor in a QD can be manipulated in situ by changing its electronic structure, for instance by means of an externally applied electrical or elastic stress field.…”

Magnetic field implementation in multibandk⋅pHamiltonians of holes in semiconductor heterostructures

“…When the magnetic field is switched on, H lutt predicts a faster increase of M than H mass or H κ (the bump at B 0 = 5.4T is due to the bonding-antibonding reversal). Since the degree of envelope angular momentum admixture is critical in determining the effective g factor of holes, 24 and we have shown that only H κ provides a consistent description of the magnetic response, Fig. 4 implies that the widely used Luttinger approximation is likely to overestimate the g factor values in confined systems.…”

“…In QDs, one can safely disregard the contribution from remote bands, and simply consider that com-ing from the HH-LH subband coupling. 24 One can see there are conspicuous differences in the energy spectra. For example, both H lutt and H mass predict that for the ground state, the B-linear term dominates over the B-quadratic (diamagnetic) one, so that its energy increases with the field.…”

“…The inclusion of strain and piezoelectric effects may be relevant for a quantitatively improved description. 24,42 Last, we compare the envelope angular momentum admixture obtained with the different Hamiltonians. In a four-band model, the hole states of cylindrical QDs are four-component spinors of the form:…”

“…[17][18][19] This approximation, hereafter referred to as the Luttinger approximation, has been successful in explaining several experimental observations in heterostructures, 3,20,21 it is implemented in the widely employed semiconductor software package nextnano, 22,23 and it is currently being used to determine the g factors of confined carriers. 14,23,24 However, a number of situations have been identified where it provides qualitatively incorrect predictions. For example, in quantum rings under axial magnetic fields, the Luttinger approximation predicts the optical gap to decrease with the field strength, 25 contrary to magneto-photoluminesence observations.…”