通过形变势弱耦合表面极化子的重整化质量

Renormalization Masses of the Weak-Coupling Surface Polaron via Deformation Potential

采用推广的线性组合算符法和拉格郎日乘子法研究了晶体中电子与SO声子和SA声子均为弱耦合极化子的重整化质量。结果表明 ,当电子接近晶体表面时 ,电子和表面声学声子耦合要比电子与表面光学声子的耦合弱。而且都与Debye截止波数有关 ;当极化子远离晶体表面时 ,电子 SO声子相互作用和电子 SA声子相互作用对极化子的重整化质量的影响可以不计 。

In the early 1970s,Ibach carried out low energy electron diffraction experiments on ZnO and other semiconductor surface.Sak,Evans and Mills studied theoretically the surface polaron in polar crystals, the Hamiltonian of the electron and surface phonon interaction was derived. Gu et al. discussed the ideal surface polaron and the weak,intermediate coupling polaron in a semi infinite polar crystal. Mills indicated that when electron moves in the surface vicinity of the crystals,the electron and surface optical phonon interaction produces a polarization cloud around the electron,whereas because of the electron surface acoustic phonon coupling the electron have been trapped at the surface vicinity motion.Theoretical results show that the surface layer of crystals may be regarded as pure 2D crystals if the distance from the surface is smaller than the radius of polarons.The effect of bulk phonons can be neglected,while surface acoustic and surface optical phonons are taken into account in the surface layer. Ueba discussed the properties of the electron,which is a interaction with both the surface optical and acoustic phonons in the surface phonon field. Toyozawa studied the quasi particle, the acoustic deformation potential (ADP) polaron,formed by the interaction of electrons with acoustic lattice vibration using the concept of the deformation potential.Recently Zhao Cui lan et al. investigated the properties of surface polaron of interaction with the deformation potential .From the point of view of confined electron,studying electron via the deformation potential interaction with acoustic phonon is more significant.The properties of surface polaron in polar crystals,which is a weak coupling with surface optical and surface acoustic phonons,was studied. In the paper ,the renormalization mass of the surface polaron is derived using Tokuda's improved linear combination operator and the Lagrange multiplier and the variational method. Two limiting cases are discussed.