高温高压下过渡金属Ru的结构相变  

Structural phase transition of Ru at high pressure and temperature

作　　者：卢志鹏[1,2,3] 祝文军[1,2] 卢铁城[1] 孟川民[2] 徐亮[2] 李绪海[2] 

机构地区：[1]四川大学物理科学与技术学院,成都610064 [2]中国工程物理研究院流体物理研究所,冲击波物理与爆轰物理重点实验室,绵阳610213 [3]武警警官学院数学与物理学系,成都610213

出　　处：《物理学报》2013年第17期397-404,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11102194);冲击波物理与爆轰物理国防科技重点实验室基金(批准号:9140C670201110C6704,9140C6702011103);中国工程物理研究院科学技术发展基金(批准号:2012B0101002);中国工程物理研究院双百人才基金(批准号:032904)资助的课题~~

摘　　要：采用基于密度泛函理论的第一性原理和准简谐晶格动力学方法对Ru的六角密排(hcp)、面心立方(fcc)、体心四方(bct)和体心立方(bcc)结构的磁性、晶格结构稳定性和高温高压下的相变进行了系统的研究.计算获得了各相结构的磁性基态及其稳定性范围,结果表明:零温下在计算的压力范围内,NM-hcp结构是Ru最稳定的结构,压力的单独作用下并没有相变的发生;NM-fcc结构是Ru的亚稳定结构,而NM-bcc和FM-bct结构在动力学上并不稳定.高温高压下Ru将发生从NM-hcp到NM-fcc结构的相变,并给出了Ru的温度压力相图.The magnetism, stabilities and phase transition of Ru in hcp, fcc, bct and bcc structures are investigated with detailed first- principles calculations based on density-functional theory and quasiharmonic lattice dynamics approximation. Magnetic ground states and stability ranges of various phases are obtained. Calculated results indicate that the non-magnetic （NM）-hcp structure is the most stable in the entire pressure range at zero temperature, and the structural transition cannot be induced by pressure alone. NM-fcc structure is a metastable phase of bulk Ru, while both the NM-bcc and ferromagnetic （FM）-bct structures are dynamically unstable. At high pressure and temperature, a transformation from NM-hcp to NM-fcc structure will occur. Finally, the pressure-temperature phase diagram of Ru is presented.

关 键 词：相变 晶格稳定性 磁性 第一性原理 

分 类 号：TG111.5[金属学及工艺—物理冶金]