压力及杂质氢对金属锂弹性特性的影响  

Influence of pressure and impurity hydrogen on the elastic property of metal lithium

作　　者：陈长波[1] 刘志明[1] 马琰铭[1] 崔田[1] 刘冰冰[1] 邹广田[1] 

机构地区：[1]吉林大学超硬材料国家重点实验室,长春130012

出　　处：《物理学报》2007年第5期2828-2832,共5页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10574053;10674053);国家自然科学基金委员会-中国工程物理研究院联合资助项目(批准号:10276016);2003年度教育部优秀青年教授资助计划;2004年度教育部新世纪优秀人才支持计划;国家重点基础研究发展计划项目(批准号:2005CB724400);教育部科技创新工程重大项目培育资金项目(批准号:2004-295)资助的课题~~

摘　　要：针对六角密堆金属锂16个原子超晶胞(supercell)、填隙一个氢原子的周期单元,采用基于密度泛函理论的平面波-赝势方法,研究了零温条件下压力及填隙氢掺杂对体系弹性性质的影响.结果表明氢掺杂导致体系的体模量增加.常压下掺杂体系的弹性常数C11,C33,C66和C12高于单质体系,剪切模量C44有所下降,而C13则与单质体系持平.压力作用下C11,C33和C66一直大于单质体系,但C12的值低于单质体系.在2GPa—4GPa压力区间内,弹性常数C13呈反常变化,小于单质体系;在高压区掺杂体系的C44和C13则高于单质体系的相应量值,压力导致掺杂体系和单质体系之间剪切模的偏离加剧.掺杂体系在压力作用下依然保持压缩模的各向同性,具有和单质体系相似的特性.The pressure effects on the elastic properties of lithium doped by hydrogen are studied using first-principles methods based on density functional theory. A supercell including 16 Li atoms in hcp lattice is constructed with a hydrogen atom interstitially doped in. The supercell is fully relaxed at 0 K. The elastic properties of the stable lattice are studied. The result shows that the bulk modulus increases after hydrogen atom is added. The elastic constants C11, C33 , C66 and C12 are larger than those of pure Li,while the shear modulus C44 is smaller. The elastic constants increase with external pressure, with C11, C33 and C66 larger than those of pure Li while C12 being smaller. C13 is abnormally lower than that of pure Li within the pressure range from 2 GPa to 4 GPa, while C44 and C13 are greater at higher pressure area. The discrepancy of shear modulus between the doped and the pure system is enhanced by external pressure. The analysis of anisotropy Δ W shows that the doped system maintains isotropic under external pressure as does pure Li.

关 键 词：第一性原理 压力效应 弹性常数 金属锂 

分 类 号：O614.111[理学—无机化学]