CAJ | 학술논문

利用第一性原理平面波赝势密度泛函理论并结合准谐德拜模型计算了闪锌矿结构ZnTe在高温高压下的弹性及热力学性质.得到了绝对零度、零压强时的晶格常数为0.6095 nm,仅比实验值(0.6103 nm)小 0.1%.计算的体弹模量及弹性常数也与实验值符合较好.根据计算的高压下的弹性常数,得到其相变点约为10 GPa,与已知的实验值一致.通过准谐德拜模型,得到了常温下(T=300 K)的德拜温度为249 K,并得到了不同温度、不同压强下的热容.热容随着压强增加而减小,在高温、高压下,热容接近于Dulong-Petit极限.
이용제일성원리평면파안세밀도범함이론병결합준해덕배모형계산료섬자광결구ZnTe재고온고압하적탄성급열역학성질.득도료절대령도、령압강시적정격상수위0.6095 nm,부비실험치(0.6103 nm)소 0.1%.계산적체탄모량급탄성상수야여실험치부합교호.근거계산적고압하적탄성상수,득도기상변점약위10 GPa,여이지적실험치일치.통과준해덕배모형,득도료상온하(T=300 K)적덕배온도위249 K,병득도료불동온도、불동압강하적열용.열용수착압강증가이감소,재고온、고압하,열용접근우Dulong-Petit겁한.
First-principles theoretical study of the elastic and thermodynamic properties of ZnTe in zinc-blende (ZB)structure at high temperature and pressure was performed by using the plane-wave pseudopotential method.The calculated lattice parameter of 0.6095 am is in excellent agreement with the experimental value of 0.6103 nm and is only 0.1% smaller.The elastic constants and bulk modulus at P=0 GPa and T=0 K are also in agreement with experimental data.From the values of the elastic constants at high pressures.the transition pressure is about 10 GPa judged by the mechanical stability conditions of cubic crystals and this is consistent with available experimental data.The Debye temperature (249 K) at the normal tempemmre (T=300 K) and the values for heat capacity(C_V) at different pressures and temperatures were also obtained by applying the quasi-harmonic Debye model.We found that the C_V decreased with the increase of pressure and was close to the Dulong-Petit limit at high temperature and pressure.