MAGNETOPHONON RESONANCES IN QUANTUM WIRES

We have investigated the magnetotransport properties of quantum wires which were fabricated on high-mobility GaAs/GaAlAs modulation-doped heterostructures by laser holography. For high temperatures (approximately 150 K), magnetoresistance structures are revealed, which are due to the occurrence of magnetophonon resonances in the wire. This effect is used to determine the polaron mass which is found to be about 10% larger than to the polaron mass in bulk GaAs. In addition, hydrostatic pressure is used to modify the electron density in these quantum wires. We observe an increase of the 1D subband energy spacing with a decreasing electron density and an enhancement of the magnetophonon resonance amplitudes.