Cyclotron Resonance Of Polarons In Realistic Heterojunctions And Its Pressure Effect

Considering a realistic interface potential, a perturbation method improved by Larsen et al has been adopted to study polarons in semiconductor heteroj unctions in a magnetic field taking into account of the interaction between an electron and both of bulk longitudinal-optical (LO) and the two branches of interface-optical (10) phonons. The relation of polaron properties dependent on external magnetic fields is obtained by discussing the polaron energies of ground states and the first excited states of Landau levels. The polaron cyclotron mass (PCM) and pressure effect are studied for weak, strong and resonant magnetic fields, respectively. The numerical results for semiconductor heteroj unctions consisting of III-V group show that the contribution from 10 phonons with higher frequency can not be neglected in weak field limit, although the bulk LO phonons are more important to influence on the PCM. As increase of a magnetic field, the contribution from the two branches of 10 phonons tends to be comparable with that from the bulk LO phonons. It becomes more and more important that the contribution to the PCM from the two branches of 10 phonons as the magnetic field increases under pressure of 40Kbar. At the same time, both of the contributions from bulk LO and 10 phonons are important. The properties of the contributions to the PCM from different branches of phonons varying with strong magnetic fields and their pressure effect are the same and negative with that for weak magnetic fields. The pressure effect of LO and 10 phonons on the PCM are important when the cyclotron resonance happens near the frequencies of different branches of phonons. The detailed 10 phonon modes should be considered in the future work especially when ones study the pressure effects of cyclotron resonance of polarons.For the further work to study the relative coefficients such as PCM in ternary mixedsemiconductors (TMC), a simple coherent potential approximation (SCPA) proposed by Ban et al is adopted to calculate the band gap for nitrided TMC semiconductor InGaN with wide gap of III-V group. The result obtained is in better agreement with experiments to show the SCPA is an acceptable approximation.