Megagauss magnetospectroscopy of EuS/PbS multi-quantum wells

Magnetotransmission studies of EuS/PbS multiquantum wells in magnetic field s up to 200 T and in the temperature range from 5 to 300 K are reported. A series of transitions are observed, which we interpret as cyclotron resonan ce transitions, i.e., the transitions between the lowest magnetic subbands. With this identification, the positions of observed resonances are satisfa ctorily described by theory when the quantum well width is larger than 100 Angstrom. For narrower quantum wells, however, the discrepancy between theo ry and experimental measurements is significant. Possible explanations for this discrepancy are discussed.