Anharmonic lattice dynamics in type-I clathrates from first-principles calculations
Anharmonic lattice dynamics in type-I clathrates from first-principles calculations
复制标题
通过第一性原理计算得出 I 型包合物中的非调和晶格动力学
DOI：
--
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
G. Santi
中科院分区：
文献类型：
--
作者：
G. Madsen;G. Santi
用第一性原理方法研究了（Sr/Ba）{sub 8}Ga{sub 16+x}Ge{sub 30-x} I型笼合物的非谐晶格动力学.发现大笼中的客体原子处于强烈的非谐势中，导致Sr rattler的偏离中心（无序）的平衡位置。Sr的最低能量模式形成一个四能级系统，隧穿分裂仅为0.04 meV。研究了非简谐振子的物理性质和中子非弹性散射谱。
The anharmonic lattice dynamics of (Sr/Ba){sub 8}Ga{sub 16+x}Ge{sub 30-x} type-I clathrates are studied using first-principles calculations. The guest atoms in the large cages are found to lie in strongly anharmonic potentials, resulting in off-center (disordered) equilibrium positions for the Sr rattler. The lowest energy modes for Sr form a four level system with a tunneling splitting of only 0.04 meV. The thermodynamical properties and the inelastic neutron scattering spectra of the anharmonic rattlers are investigated.