自由边界条件钙钛矿结构晶格振动的研究  

Lattice Vibration of BatiO_3 in Free Boundary Condition

作　　者：何山[1] 

机构地区：[1]中山大学物理系电介质实验室,99硕广州510275

出　　处：《中山大学研究生学刊（自然科学与医学版）》2001年第1期7-13,共7页Journal of the Graduates Sun YAT-SEN University(Natural Sciences.Medicine)

摘　　要：本文用最近邻力系数和次近邻力系数f,k,g,给出了n=N_1×N_2×N_3三维有限自由BaTiO_3晶体的简谐振动方程。对n由75增大到4800的不同体系进行了数值计算。观察到方程的解随着n的增大而收敛的性质。给出了体系在自由三维情况下的简谐振动频谱,一些低频模的花样。找到了导致结构不稳定的晶化软模。对旋转模在循环边界条件下发生的变化进行了说明。By representing the nearest-neighbor force const and the second-nearest- neighbor force oonst f、k、g, the harmonic vibrational equations of a n=N_1×N_2×N_3 finite BaTiO_3 lattice in three-dimension are given. The numerical calculation for different systems from n=75 to 4000 has been done. The solution of the equations getting conver- gence with the increase of n has been observed. The vibrational frequency spectrum of the lattice, some mode of low frequency, and the soft mode which causes the instability of the lattice have been found.

关 键 词：晶格振动 频谱 自由边界条件 模花样 软模 钙钛矿 钛酸钡 

分 类 号：O733.1[理学—晶体学]