Inter-band magneto-absorption in a Ga0.3In0.7As-InP strained layer superlattice

The inter-band optical absorption of a GaxIn1-xAs-InP superlattice has been studied in magnetic fields up to 16 T. From the band gap of the sample, the alloy composition in the GaxIn1-xAs layers is found to be x=0.32, giving a lattice mismatch of 1.1% and a splitting of 75 meV between the heavy hole (mJ=+or-3/2) and light hole (mJ=+or-1/2) band edges. Transitions have been observed between the Landau levels of the N=1 electron and heavy hole sub-bands at energies up to 250 meV above the band edge. Comparison with cyclotron resonance measurements on the same sample shows that the N=1 heavy hole sub-band is highly non-parabolic, and this is compared with theoretical predictions.