The effect of hydrostatic pressure on a Ga0.47In0.53As/InP heterojunction with three electric sub-bands

We report the first experiment under hydrostatic pressure for GalnAs/InP heterojunction with three electric sub-bands populated. The total population decreases from 6.04 x 10(11) cm(-2) to 5.09 x 10(11) cm(-2) (16%) for pressure up to 15 kbar. Although this change is bigger than the population of the third sub-band we found it to be populated even for the highest pressure applied. This observation, as well as the decrease of the gaps in energy between the electric sub-bands, prove the action of a hydrostatic pressure upon the positions of the electric sub-bands in the quantum well. A study in parallel magnetic fields allows us to work out the value of: (Delta(zo))(2-)(Delta z(1))(2) difference in the spread of the wavefunction of the ground and first excited sub-bands. The increase of this value with pressure proves a broadening of the quantum well. We observe a fall of Hall mobility of 2% kbar(-1) while the increase of effective mass with pressure is only 1 +/- 0.1% kbar(-1) for this sample and the contribution of inter-sub-band scattering has been found to decrease with pressure.