奇异的BiS_2层超导体电子结构的第一性原理研究  

THE ELECTRONIC STRUCTURE OF NOVEL BiS_2-BASED LAYERED SUPERCONDUCTOR:FIRST-PRINCIPLES STUDIES

作　　者：杨聚宝[1] 刘畅[1] 王广涛[1] 

机构地区：[1]河南师范大学物理系信息与工程学院,新乡453007

出　　处：《低温物理学报》2013年第5期386-390,共5页Low Temperature Physical Letters

基　　金：国家自然科学基金(批准号:11274095)资助的课题~~

摘　　要：通过第一性原理计算,我们研究了新近发现的BiS2层超导体化合物LaO1-x Fx BiS2的态密度、能带结构和费米面等性质,并与LaOFeAs进行比对.当x=0时,体系的态密度与能带结构都表明LaOBiS2是一个拥有0.15eV带隙的绝缘体,随着F的掺杂,体系逐渐变为导体.x=0.5时,有四条能带穿越费米能级,这四条能带主要源自Bi原子的Px和Py轨道.通过比较发现,LaO1-x Fx BiS2化合物中的费米面嵌套效应比LaOFeAs中的弱.By means of the first-principles calculations, we studied the density of states, band structure and Fermi surface nesting of the recently discovered BiS2 layered superconductor LaO1-xFxBiS2. At x= 0, the density of state and band structure of LaOBiS2 indicate the compound is a insulator with a band gap of 0. 15eV. It becomes metal with F-doping. At x=0. 5, there are four bands crossing the Fermi level. These four bands are mostly derived from the Px and Py orbitals of Bi atoms. Compared with the typical Fe-As based superconductor LaOFeAs, the Fermi surface nesting of LaO1-xFxBiS2 is not as strong as that of LaOFeAs.

关 键 词：第一原理计算 费米面嵌套 超导 

分 类 号：O469[理学—凝聚态物理] O511[理学—电子物理学]