M. Kemerink et al., EXCHANGE INTERACTION IN P-TYPE GAAS ALXGA1-XAS HETEROSTRUCTURES STUDIED BY MAGNETOTRANSPORT/, Physical review. B, Condensed matter, 57(11), 1998, pp. 6629-6635
Low-temperature magnetotransport experiments have been performed on a
p-type GaAs/AlxGa1-xAs quantum well. From activation measurements on S
hubnikov-de Haas conduction minima it was found that ex change interac
tions can be of great importance for both odd and even filling factors
and strongly influence the observed periodicity. Furthermore, it was
found that the temperature dependence of Shubnikov-de Haas oscillation
s in the low-magnetic-field regime could not be explained within a sin
gle-particle model based on a solution of the full Luttinger Hamiltoni
an in a magnetic field. Numerical simulations of Shubnikov-de Haas spe
ctra, based on a model that treats hole exchange interactions in a sim
plified manner, show unambiguously that exchange driven enhancement of
hole ''spin'' splittings are extremely important at magnetic fields a
s low as 1.5 T. Also, the inclusion of a valence-band warping in the c
alculations is shown to be essential. Qualitatively, most experimental
observations could be described within the presented model. Our resul
ts imply that, in any hole system, the effective masses obtained from
temperature-dependent SdH measurements are to be treated with extreme
care as they can deviate from their single-particle value by as much a
s a factor of 2.