HIGH-FREQUENCY CONDUCTIVITY OF ELECTRONS IN DOUBLE-QUANTUM WELLS UNDER AN INPLANE MAGNETIC-FIELD

The high-frequency response of electrons in double quantum wells (DQWs ) under an in-plane magnetic field is considered. The absorption, the Voigt effect and the transverse dipole moment due to electron transiti ons between tunnel-coupled levels are calculated for excitation by an electric field parallel to the 2D plane; the depolarization held, whic h is perpendicular to the 2D plane, is also taken into account. Strong modification of the intersubband absorption spectrum (the appearance of two absorption peaks, which demonstrate different collisionless bro adening and shift) is found under increasing magnetic field. The spect ral dependencies of the Voigt effect and induced dipole moment are cal culated. Such dependencies are different in essence for small magnetic fields, for which both tunnel-coupled states are occupied; for interm ediate magnetic fields, for which the Fermi level intersects the antic rossing gap; and for large fields, for which the electrons are localiz ed in two valleys of the lowest level. Numerical estimates of these ef fects are presented for typical DQW structures.