三维复式晶格的热容研究

The Study on Thermal Capacity of Three-dimensional Multiplex Lattice Crystal

采用一种类似于简单晶格德拜模型的方法,研究了三维复式晶格的声频支和光频支格波对晶格热容的影响,得到了三维复式晶格的热容表达式。在高温极限情况下,声频支和光频支格波对晶格热容都有贡献,计算结果与杜隆-珀替定律一致;在低温极限情况下,声频支格波对晶格热容有贡献,光频支格波可以忽略。

The method similar to Debye model which uses simple lattice are adopted and the effects of acoustical and optical phonon branches on the lattice thermal capacity are investigated,furthermore,the thermal capacity expressions of three-dimensional multiplex lattice crystal are obtained.In the high-temperature conditions,all the acoustical and optical phonon branches are contributed to thermal capacity,and the calculated results are in accordance with the classic Dulong-Petit law.In the low-temperature conditions,the main contribution to thermal capacity belongs to acoustical phonon branches and the optical phonon branches can be ignored.