【作者】 刘勇；

【导师】 朱俊；

【作者基本信息】 四川大学 ， 原子与分子物理， 2007， 硕士

【摘要】 BeTe和BeSe是制作光电仪器、半导体激光器以及发光二极管很常用的半导体材料。虽然它们在技术方面已得到广泛的应用，在高压下的性质也得到了大量地研究，但是在高压下的一些基本问题（包括其几何结构、电子结构及键的机制等）还未获得解决。近年来，无论是在实验上还是理论上，研究材料在高压下的性质一直是个热门课题。本文首先利用平面波赝势密度泛函理论研究了BeTe从闪锌矿结构到B8结构的相变以及这两种结构的基本性质参数，包括晶格常数a、体弹模量B₀、体弹模量对压强的一阶导数B′₀以及弹性常数(C₁₁、C₁₂、C₄₄)。依据焓相等原理，我们发现从闪锌矿结构到B8结构的相变压强为32.76GPa，计算结果与实验及其它理论值相符。其次利用平面波赝势密度泛函理论研究了BeSe从闪锌矿结构到NiAs结构的相变以及这两种结构的基本性质参数，包括晶格常数a、体弹模量B₀、体弹模量对压强的一阶导数B′₀以及弹性常数(C₁₁、C₁₂、C₄₄)。依据焓相等原理，我们发现从闪锌矿结构到NiAs结构的相变压强为57.65GPa，计算结果与实验及其它理论值相符。更多还原

【Abstract】 As semiconductors, BeTe and BeSe are the most suitable candidates for fabrication of photovoltaic devices, semiconductor lasers and light emitting diodes. Despite the technological developments of BeSe, the high pressure behavior of BeSe has been the subject of considerable attention. Many fundamental problems for BeSe under high pressure condition, such as the structural, electronic and bonding mechanisms, still remain unsolved. Recently, properties of material at high pressures and high temperatures have been the objects of intensive experimental and theoretical investigations.Firstly, the transition phase of BeTe from the ZB to the RS structure is investigated by ab initio plane-wave pseudopotential density functional theory, and the lattice constant a, the bulk modulus B₀ and the first order pressure derivative of bulk modulus B₀^’ are obtained. According to the usual condition of equal enthalpies, we find that the transition from the ZB structure to the NiAs structure occurs at the pressure of 32.76 GPa, as is well consistent with the experimental data and other theoretical results.Secondly, the transition phase of BeSe from the ZB to the NiAs structures is also investigated. It is found that the transition from the ZB structure to the NiAs structure occurs at the pressure of 55.4 GPa, as is well consistent with the experimental data and other theoretical results.更多还原