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Pressure dependence of the structure of liquid metals with covalent and ionic bonds

具有共价键和离子键的液态金属结构的压力依赖性

基本信息

批准号：
13640372
负责人：
TSUJI Kazuhiko
金额：
$ 2.18万
依托单位：
Keio University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640372/
关键词：
liquid metals high pressure synchrotron radiation structure x-ray diffraction

项目摘要

The application of pressure to liquids causes volume reduction and change of interatomic interaction. Especially in liquid metals with covalency in the bands, the interatomic interact ion strongly depends on the volume. In this study we have investigated the effects of pressure on the structure of liquids with covalency and ionicity in the bonds, such as liquid III-V and II-VI compounds.X-ray diffraction for liquid metals has been performed by using synchrotron radiation. From the pressure dependences of the structure factor and pair distribution function of liquids, it is concluded that the local structure of liquid III-V compounds shows different pressure dependence from that of crystals and systematic variation with atomic number and ionicity. With increasing pressure, the local structure of liquid GaSb contracts nonuniformly and its coordination number increases. In liquid InSb which has larger ionicity than that of GaSb, the change in the pressure dependence of the local structure was observed at about 10 GPa from nonuniform to uniform contract ion. The local structure above 10 GPa is different from those of the high pressure crystal l ine phases. In liquid CdTe, a sharp structural transformation was observed around 2 GPa from the zincblende-like to the rocksalt-like local structure. This pressure-induced structural transformation is similar to that in the crystal, in contrast to the different pressure dependence of the liquid structure from that of the crystal in Si, Ge and III-V compounds. This difference should originate from a large ionicity in the bonds in CdTe.

对液体施加压力会引起体积减小和原子间相互作用的变化。特别是在带间共价的液态金属中，原子间相互作用离子强烈地依赖于体积。本文研究了压力对具有共价性和离子性的液态化合物（如III-V族和II-VI族化合物）结构的影响，并利用同步辐射对液态金属进行了X射线衍射。从液体的结构因子和对分布函数的压力依赖性，可以得出结论：液体III-V族化合物的局域结构表现出与晶体不同的压力依赖性和随原子序数和离子性的系统变化。随着压力的增加，液态GaSb的局域结构不均匀收缩，配位数增加。在离子度比GaSb大的液态InSb中，在约10 GPa下观察到局域结构的压力依赖性从非均匀收缩离子到均匀收缩离子的变化。10 GPa以上的局部结构不同于高压下的晶线相。在液态CdTe中，在2GPa附近观察到从闪锌矿状到岩盐状局部结构的急剧结构转变。这种压力诱导的结构转变是类似的晶体中，在不同的压力依赖性的液体结构从硅，锗和III-V族化合物中的晶体。这种差异应该源于CdTe中键的大离子性。