弱耦合多原子半无限晶体中磁极化子的激发能量

近年来国内外对多原子极性晶体中磁极化子性质的研究十分活跃,Zorkani等采用变分法计算了束缚磁极化子的基态能量,Kandemir等采用束缚朗道态讨论了二维大磁极化子的基态和第一激发态能量,国内一些学者采用微扰法和新颖算符法讨论了多原子极性晶体中表面和体磁极化子的性质。采用线性组合算符和幺正变换,研究磁场中多原子半无限极性晶体中电子和光学声子弱耦合相互作用所产生的极化子的第一激发态能量及平均声子数。结果表明:当电子无限接近晶体表面时,磁极化子的基态能量仅为Landau能量;第一激发态能量为Landau基态能量的2倍;平均声子数等于各支与电子耦合的体光学声子数和表面光学声子数之和。而当电子处于晶体深处时,磁极化子的基态能量却为Landau基态能量与各支体光学声子以及表面光学声子分别耦合的能量之和;第一激发态能量仍为Landau基态能量的2倍;平均声子数等于各支与电子耦合的体光学声子数和与所处深度有关的各支体光学声子数之和,而与各支表面光学声子无关。

Excitation Energy of Weak-coupling Magnetopolaron in Polyatomic Semi-infinite Polar Crystals

With the development of the solid theories and experimental technology,more and more scholars at home and abroad are conducting research on the properties of the magnetopolaron in crystals,there are already many contributions in this field.Peeters et al.studied the properties of the magnetopolaron using Feynman's path integral method.Wei and her co-workers discussed the properties of an interface magnetopolaron using Green-function method.Zorkani et al.calculated the ground state energy of bound magnetopolaron using the variational method.Larsen studied the properties of the two-dimensional polaron using an original operator method.Xiao et al.discussed the properties of the surface polaron using a linear-combination operator method.Matsura and Lepine studied the problems of polaron which contains many LO phonon branches in polyatomic crystals.Xiao and Hu and other co-workers investgated the many properties of the surface polaron and bulk polaron in polyatomic crystals.Recently Wang and Xiao discussed the excitation state energy of polaron in(polyatomic) crystals for the first time.The first excitation energy and the mean number of the weak-coupling magnetopolarons in the polyatomic semi-infinite polar crystals were studied by using a linear-combination(operator) and unitary transformation methods.The results showed that when the electron is approaching infinitely to the surface of crystals,the ground state energy of the magnetopolaron is only the Landau ground state energy,the first excitation energy of the magnetopolaron is twice the Landau ground state energy,and the mean(number) of phonon is equal to the number of LO phonons and that of SO phonons that each one has coupling with the electron.When the electron is situated in the depth of crystals,the ground state energy of the magnetopolaron is equal to the Landau ground state energy and the energy of LO phonons and SO phonons that each one has coupling with the electron,the first excitation energy of the magnetopolaron is also twice the Landau ground state energy, and the mean number of phonon is equal to the phonon-number of LO phonons concerning depth and that of LO phonons that each one has coupling with the electron,but it is not related to the each branch of SO phonon.