Structures and phase transitions of ScH_3 under high pressure  

作　　者：孔博 周筑文 陈德良 令狐荣锋 

机构地区：[1]School of Physics & Electronic Sciences,Guizhou Normal College [2]College of Physical Science and Technology,Sichuan University

出　　处：《Chinese Physics B》2013年第5期429-433,共5页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (Grant No. 11174214);the Specialized Research Fund for the Doctoral Program of Higher Education, China (Grant No. 20090181110080);the National Basic Research Program of China (Grant No. 2011CB808201);the Special Project for Research Conditions of High-level Talents of Guizhou Province, China (Grant No. TZJF-2008-42);the Science Foundation of Education Bureau of Guizhou Province, China (Grant No. 2010053)

摘　　要：The structures and the phase transitions of ScH3 under high pressure are investigated using first-principles calcula- tions. The calculated structural parameters at zero pressure agree well with the available experimental data. With increasing pressure, the transition sequence hcp （GdHa-type）→ C2/m →fcc→4hcp （YH3-type）→Cmcm of ScH3 is predicted first; the corresponding transition pressures at 0 K are 23 GPa, 25 GPa, 348 GPa, and 477 GPa, respectively. The C2/m symmetry structure is a possible candidate but not a good one as the intermediate state from hexagonal to cubic in ScH3. On the other hand, via the analysis of the structures of hexagonal SCH2.9, cubic ScH3, and cubic ScH2, we find that the repulsive interactions of H-H atoms must play an important role in the transition from hexagonal to cubic.The structures and the phase transitions of ScH3 under high pressure are investigated using first-principles calcula- tions. The calculated structural parameters at zero pressure agree well with the available experimental data. With increasing pressure, the transition sequence hcp （GdHa-type）→ C2/m →fcc→4hcp （YH3-type）→Cmcm of ScH3 is predicted first; the corresponding transition pressures at 0 K are 23 GPa, 25 GPa, 348 GPa, and 477 GPa, respectively. The C2/m symmetry structure is a possible candidate but not a good one as the intermediate state from hexagonal to cubic in ScH3. On the other hand, via the analysis of the structures of hexagonal SCH2.9, cubic ScH3, and cubic ScH2, we find that the repulsive interactions of H-H atoms must play an important role in the transition from hexagonal to cubic.

关 键 词：ab-initio calculations phase transitions high pressure 

分 类 号：O521.2[理学—高压高温物理]