Magnetic-field enhancement of interface-phonon effects on quasi-two-dimensional magnetopolarons

The binding energy of a polaron confined in the quantum well of GaAs/Ga1-xAlxAs double heterostructures is calculated as a function of the magnetic field applied in the direction of growth. We have also calculated the oscillator strength of electron-phonon interaction for transitions from various excited states to the ground state of the polaron. Every type of optical-phonon mode that can exist in such structures within the continuum model is considered separately. It is found that the magnetic field greatly enhances the interface-phonon part of the polaron effect. For quantum wells of widths 150 A or smaller, the interface modes dominate all polaronic phenomena we have encountered when B1 T. For quantum wells of widths up to 100 A, contributions from confined bulk phonon modes are almost negligible in magnetic fields B1 T.