抛物量子点中强耦合束缚极化子的性质

采用Pekar类型的变分方法研究了抛物量子点中强耦合束缚极化子的基态和激发态的性质。计算了束缚极化子的基态和激发态的能量、光学声子平均数。讨论了量子点的有效束缚强度和库仑束缚势对基态能量、激发态能量以及光学声子平均数的影响。数值计算结果表明:量子点中强耦合束缚极化子的基态和激发态能量及光学声子平均数均随量子点的有效束缚强度的增加而减小,基态、激发态能量随库仑束缚势的增加而减小,光学声子平均数随库仑束缚势的增加而增大。

Properties of Strong Coupling Bound Polaron in Parabolic Quantum Dot

In recent years,the lots of novel effects of the quantum dots systems have attracted more and more physicists.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.Kandemir and Altanhan used the Lee-Low-Pines transformation to calculate the polaronic effects for an electron confined in a parabolic quantum dot.Zhu and Gu investigated the ground states and self-energy of the weak-coupling polaron in a parabolic quantum dot by using the second order Rayleigh-Sch rdinger perturbation theory.Li and Zhu investigated the strong-coupling polaron in a parabolic quantum dot by the Landau-Pekar variational treatment.It is shown that both the polaron binding energy and the average number of virtual phonons around the electron decrease with increasing the effective confinement length.Other investigations indicate that the bound interaction of the Coulomb potential plays an important role on the property of optical polaron.Es-shai et al.investigated the impurity bound polaron in a cubic quantum dot using the variational approach.Melnikov et al.applied the adiabatic variational method to calculate the polaron energy shift in a spherical quantum dot.Satori et al.attained the binding energy of a bound polaron to shallow donor impurity in spherical quantum dot using a vatiational approach within the effective mass approximation.One of this paper's authors achieved the vibration frequency and the average number of phonons of the strong-coupling bound magnetopolaron in a parabolic quantum dot by using the linear combination operator and unitary transformation methods.In the present paper,by using the variational method of Pekar type,we have studied both the ground state energy and the excited state energy of strong coupling bound polaron in parabolic quantum dot.The polaron energies in both the ground state and the excited state,the average number of virtual phonons around the electron were calculated.Their dependence on the effective confinement strength and the Coulomb potential was depicted.