Far infrared magneto-optics of InAs1-xPxalloys under hydrostatic pressure

Far infrared (FIR) magneto-optical experiments on InAs 1-x P x alloys (x=0.22, 0.31 and 0.66) under pressure are reported. The pressure coefficients of the effective mass for the three compositions have been determined. These results are in agreement with previous work on the effective mass dependence on composition and the energy gap dependence on pressure. The hydrogenic model of shallow impurities has been successfully applied to analyse FIR photoconductivity spectra. Central cell splitting of the shallow donor lines has been observed in an alloy system for the first time. No evidence is found for any non- Gamma impurity levels which are resonant with the conduction band at atmospheric pressure but which can be introduced into the forbidden energy gap at pressures below 15 kbar as suggested by other workers.