磁场对氮化物抛物量子阱中束缚极化子的影响

Influence of Magnetic Field to Bound Polaron in Nitride Parabolic Quantum Well

采用改进的Lee-Low-Pines中间耦合方法研究了在外磁场作用下纤锌矿氮化物抛物量子阱中极化子能级,给出不同磁场下极化子基态能量、结合能随阱宽L的变化关系以及能量随磁场强度B变化的函数关系。在计算抛物量子阱材料中考虑了纤锌矿GaN和Al0.3Ga0.7N构成的抛物量子阱中材料中准LO和准TO声子模的各向异性以及外磁场对极化子能量的影响。结果表明:纤锌矿氮化物抛物量子阱材料中电子-声子相互作用和外磁场对极化子能级有明显的影响。极化子基态能量、结合能随阱宽的增加而减小,随磁场的增加而增大,电子-声子相互作用使极化子能量降低,并且GaN/Al0.3Ga0.7N抛物量子阱对极化子的束缚程度比GaAs/Al0.3Ga0.7As抛物量子阱强,因此,在GaN/Al0.3Ga0.7N抛物量子阱中束缚于杂质中心处的电子比在GaAs/Al0.3Ga0.7As抛物量子阱中束缚于杂质中心处的电子稳定。

In the adiabatic approximation, the energy level of a polaron in a wurtzite nitrid parabolic quantum well structures （PQW） are studied under an external magnetic filed. The ground state, binding energies of polaron change with the width of the quantum well and the external magnetic fields are obtained. The effects of the anisotropy of confined LO （TO）-like phonon modes and external magnetic filed on energy levels are considered in the calculation. The results show that the electron-phonon interaction and the magnetic filed strongly affect energy levels of a polaron in wurtzite nitrid PQW. The energy of the polaron decreases with increasing well width and increases with increasing magnetic fields strength. The electron-phonon interaction tends to lower the polaron energy levels. In addition, the bound degree of the GaN/Al0.3Ga0.7 N PQW to the polaron is stronger than the GaAs/Al0.3Ga0.7As PQW. Therefore, the electron coupled to a hydrogenic impurity in the GaN/Al0.3Ga0.7N parabolic quantum well is stabler than that in the GaAs/Al0.3Ga0.7AS parabolic quantum well.