闪锌矿结构链中的非线性局域模(英文)

Intrinsic Localized Modes in an Anharmonic Sphalerite structure Lattice

利用数值计算研究近邻原子质量和作用力常数均不同的一维链中的非线性局域模，该模型模拟闪锌矿结构晶体中〈１１１〉方向一列原子的非线性振动。在考虑近邻原子间相互作用势函数中的四次方非线性项时，在相应线性系统频带的光学支上面和禁带中发现了非对称分布准奇偶宇的局域模。在自由边界条件下，表面模也存在。本文所得结果与前人对金刚石结构晶体模型的结果有所不同。

We study nonlinear vibrational localized modes in one dimensional diatomic chain with different masses and alternating force constants between nearest neighbors by numerical calculation.This model simulates a row of atoms in the 〈111〉 direction of a sphalerite structure crystal.The inclusion of quartic anharmonicity in the nearest neighbor interaction potential produce asymmetric intrinsic localized modes with frequencies above the optical branch and in the gap of the corresponding linear system.The modes with quasi even parity or quasi odd parity obtained in this paper are somewhat different from those of diamond structure lattice.Surface modes also occur when we consider the free end boundary condition.