中文摘要：

通过对单斜与立方氧化铜两种晶体结构的模型建立、几何优化、声子谱以及热力学计算与分析,发现单斜和立方两种结构的氧化铜的热力学不稳定性主要是由O原子造成的,其中单斜氧化铜的热力学性质无论是低温时还是高温时都由Cu原子和O原子共同主导,而立方氧化铜的热力学性质在低温时由Cu原子主导,高温时由O原子主导;从声子态密度的计算分析获得了两种结构氧化铜的热力学性质;同时得出了单斜氧化铜晶体和立方氧化铜晶体之间的相转变热力学温度为1 013.28K。

英文摘要：

The crystal structure models of monoclinic and cubic copper oxide are established in this paper. Thenthe geometry optimization, phonon spectra and the thermodynamic properties are calculated and analyzed. Thefollowing conclusions are obtained. Thermodynamic instability of copper oxide is mainly dominated by the oxy-gen atom. The thermodynamic properties of monoclinic copper oxide is dominated by the copper atom and oxy-gen atom in both low temperature and high temperature. But the thermodynamic properties of cubic copper ox-ide is dominated by the copper atom in low temperature, and it is dominated by the oxygen atom in high tem-perature. The thermodynamic properties of two kinds of structural copper oxide are dominated by calculation ofphonon density. The thermodynamic temperature of the phase transition between the monoclinic crystal and thecubic copper oxide crystal is 1 013.28 K.