Cyclotron masses and g -factors of hybridized electron-hole states in InAs GaSb quantum wells

Using the eight-band k•p model and the Burt-Foreman envelope function theory to perform self-consistent calculations, we have studied the effect of electron-hole hybridization on the cyclotron masses m* and the effective g -factors g* of two-dimensional quasiparticles in InAs GaSb quantum wells under a magnetic field applied perpendicular to the interfaces. We can modify the degree of hybridization by changing the InAs and/or GaSb layer width, or by inserting a thin AlSb barrier. While electron-light-hole hybridization dominates at both low and high fields, due to a sequence of anticrossings between electronlike and heavy-holelike levels, there is also an important contribution from heavy-hole states to the strong hybridization in the intermediate field range. The field-dependence of the hybridized energy eigenstates is manifested in the variations of m* and g*. Characteristic discontinuous changes of both m* and g* appear at each anticrossing, resulting in a magnetic-field-driven oscillating behavior of these quantities for electronlike states of a given Landau level index. The electron g -factor can change sign when two eigenstates anticross. Hybridization of electron and hole states enhances the electron effective mass, and we have found a complicated dependence of this effect on the interaction strength. Without inserting an AlSb barrier, the strong interaction between the electronlike and the light-holelike states at low magnetic fields produces a large level repulsion, and hence relatively small effective masses and g -factors associated with these states. Intermediate interaction leads to weaker level repulsion and therefore very heavy electron cyclotron masses as well as large g -factors associated with the lowest Landau levels. A weak interaction only enhances the cyclotron masses of the electronlike states slightly. The hole effective masses change with both the magnetic field and the sample structure in a more complicated fashion.