平均键能E_m的物理内涵探讨

STUDY ON PHYSICAL CONNOTATION OF AVERAGE BOND ENERGY E_m

在面心立方 (fcc)、体心立方 (bcc)和六角密堆积 (hcp) 3种不同结构晶体的自由电子能带模型中 ,发现 4个最低能带与 5个次低能带本征值的平均能量 (称为平均键能 ,Em)与费米能级 (EF)相当接近 ;并进一步在hcp结构的钛(Ti)、锆 (Zr)和铪 (Hf)以及bcc结构的铁 (Fe)等金属中 ,采用从头赝势能带计算方法和平均键能计算方法 ,证实在这些金属的实际能带中 ,平均键能 (Em)值仍然非常接近于费米能级 (EF)值 .该发现有助于进一步了解平均键能(Em)的物理内涵 .

In free electron band model of three different crystal structures, face-centered cubic (fcc),body-centered cubic (bcc), and hexagonal close-packed (hcp) structures,we fine that the average energy of the four lowest band eigenvalues and the five sub-low band eigenvalues (called as average bond energy E-m) is rather close to Fermi level E-F. Meanwhile,we also confirm that this conclusion still holds for the practical band in some metals,such as Ti,Zr and I-If with hcp structure as well as Fe with bcc structure etc.,using ab initio pseudopotential and average bond energy methods. Thereby one can further understand the physical connotation of average bond energy E-m.