ZEEMAN SPLITTING IN THE EXTREME QUANTUM LIMIT THROUGH CYCLOTRON-RESONANCE ON 2-DIMENSIONAL GAAS AT HIGH-PRESSURE

Cyclotron resonance measurements on a GaAs heterojunction in the extre me quantum limit are presented. It has been reported recently that a n ew splitting appears for filling factors less than 1/6. We have applie d hydrostatic pressure in order to investigate the dependence on elect ron g-factor, since a pressure of similar to 8 kbar halves the g-facto r, yet changes the effective mass by only similar to 5%. The critical filling factor, defined as the point where the two split resonances ha ve equal intensity, is found to be strongly reduced with pressure. A g eneral relationship is presented for the dependence of the critical fi lling factor on the Zeeman splitting.