Magnetic-circular-dichroism study of heavy- and light-hole g factorsin ${\mathrm{In}}_{\mathrm{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$As/InP quantum wells

Intersubband transitions in ${\mathrm{In}}_{\mathrm{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$As/InP quantum wells have been studied by magnetic circular dichroism (MCD) of the absorption. The g values of the heavy and light holes in the different subbands are deduced from the intensity dependence of the MCD signals on the applied magnetic field: ${\mathrm{g}}_{\mathrm{hh}1\mathrm{}}^{\mathrm{*}}$=-0.68±0.1, ${\mathrm{g}}_{\mathrm{hh}2\mathrm{}}^{\mathrm{*}}$=-1.81±0.4, and ${\mathrm{g}}_{\mathrm{lh}1\mathrm{}}^{\mathrm{*}}$=8.87±1.2. These results are in good agreement with effective-mass-theory calculations and allow one to estimate the in-plane effective masses of the second heavy-hole (${\mathrm{m}}_{\mathrm{hh}2\mathrm{}}^{\mathrm{*}}$=0.${85\mathrm{m}}_0$) and the first light-hole (${\mathrm{m}}_{\mathrm{lh}1\mathrm{}}^{\mathrm{*}}$=0.${17\mathrm{m}}_0$) subbands. An observed increase of the half-width of the subband transitions with increasing transition energy and increasing magnetic field is qualitatively explained by statistical fluctuations of the quantum-well width.