MAGNETIC QUANTUM OSCILLATIONS IN IN0.53GA0.47AS IN0.52AL0.48AS MULTIQUANTUM-WELL OBSERVED BY MILLIMETER-WAVE RESPONSE/

We report on millimeter wave measurements of an In0.53Ga0.47As/In0.52A l0.48As multiquantum well fabricated by gas source molecular beam epit axy. Transmission experiments with the millimeter waves (16-110 GHz) w ere carried out as a function of the magnetic field up to 10 T at temp eratures down to 0.6 K. The quantum oscillations corresponding to the Shubnikov-de Haas effect are observed in the amplitude and phase of th e transmitting waves. The effective mass can be estimated as 0.058m(0) for the 1st-subband electron. In spite of a small Fermi energy of 27 meV for the 1 st subband, the enhancement of an effective mass is 30% over the bulk band-edge mass of 0.041m(0). The large difference origin ates from the resonant polaron coupling due to a fundamental GaAs-like LO-phonon in addition to the band nonparabolicity of the In0.53Ga0.47 As well.