立方氮化硼准简谐近似的有效温度范围  

The valid temperature range of quasi-harmonic approximation for cubic boron nitride

作　　者：谢远亮[1] 吴颖[1] 徐恩生[1] 

机构地区：[1]沈阳航空航天大学理学院,辽宁沈阳110136

出　　处：《沈阳航空航天大学学报》2011年第3期78-80,共3页Journal of Shenyang Aerospace University

基　　金：辽宁省教育厅科研项目(项目编号:20060656)

摘　　要：为减少立方氮化硼高温高压理论研究中的计算量,确定准简谐近似(QHA)的有效温度范围,通过第一原理晶格动力学计算,得到了零压下温度从300 K到3 000 K的热胀系数、定容热容、等温体积模量及格林雷森系数等与温度的关系。计算模拟结果表明,对立方氮化硼准简谐近似的有效温度范围约为其德拜温度的1.8倍,且在该温度范围里,格林雷森系数随温度缓变,约为1.0,即在此温度范围里准简谐近似是可靠的。In order to reduce computational expense and determinate the valid temperature range of quasi-harmonic approximation（QHA） for cubic boron nitride,the thermal properties of cubic boron nitride,including isochoric heat capacity,isothermal bulk modulus,Gruneisen parameter,thermal expansion coefficient,are studied using first principle lattice dynamics in zero pressure and in temperature between 300K and 3000K.It shows that QHA is valid when temperature is up to 1.8 times Debye temperature and that Gruneisen parameter,being about 1.0,varies slowly with temperature,indicating that QHA is valid in the range of temperature.

关 键 词：高温高压 格林雷森系数 准简谐近似 

分 类 号：O481[理学—固体物理]