抛物量子点中强耦合磁极化子的性质

采用Pekar类型的变分方法研究了抛物量子点中强耦合磁极化子的基态和激发态的性质。计算了基态和激发态磁极化子的束缚能以及磁极化子的共振频率。讨论了这些量对回旋频率和有效限制强度的依赖关系,以及磁极化子光学声子平均数的性质,结果表明:由于Zeeman劈裂,抛物量子点中磁极化子的回旋共振频率劈裂为两支。基态和激发态磁极化子的束缚能以及磁极化子的共振频率都随回旋频率的增加而增大,随量子点的有效束缚强度的增大而减小。

Effect of Strong Coupling Magnetopolaron in Parabolic Quantum Dot

With the advance in the nanofabrication technology,there has been a great deal of interest in the investigation of quasi-zero-dimensional electronic systems(quantum dots).Because of the wide device applications and a lot of new physical effects in such structures,understanding the electronic properties of these systems is of particular importance.Several studies have already been carried out on the interaction of the electrons with longitudinal-optical(LO) phonons in quantum dots.Recently,Zhu and Kobayashi used the Landau-Pekar variational treatment to study the strong coupling polaron binding energy of the ground state and the average number of virtual phonons around the electron in quantum dots in the presence of magnetic fields.Taking into account the electron-bulk LO-phonon interaction,Kandemir and Altanhan used the Lee-Low-Pines transformation to calculate the polaronic effects for an electron confined in a parabolic quantum dot in a uniform magnetic field.Zhu and Gu investigated the polaronic states in a parabolic quantum dot by using the second order Rayleigh-Schrodinger perturbation theory.It is shown that the absolute values of the ground state energy correction and the excited state energy correction as well as the relevant transition energies increase with decreasing the size of the quantum dot.The results also indicate that the polaron effects in small quantum dots are stronger than those in the corresponding bulk materials.In the papers of Zhou and Gu,by using the variational method of Pekar type,the ground state and the first excited state of the strong coupling magnetopolaron in cylinder-shape and disk-shape quantum dot were considered.The results show that,with the increasing cyclotron frequency and the confinement strength,the magnetopolaron binding energies in both the ground state and the excited state,and the resonance frequency of magnetopolaron are enhanced.However,the properties of magnetopolaron in the excited state in parabolic quantum dot has not been studied so far.In this paper,by using the variational method of Pekar type,both the ground state and the excited state of strong coupling magnetopo-laron in parabolic quantum dot were studied.The magnetopolaron binding energies in both the ground state and the excited state,and the resonance frequency of magnetopolaron were calculated.Their dependence on the cyclotron frequency and the confinement strength was depicted.