YBa_2Cu_3O_7能隙及低温物性的第一原理计算  

First-Principles Calculation of Energy-Gap and Low-Temperature Physical Character in YBa_2Cu_3O_7

作　　者：吴建华[1] 耿兴国[1] 李金山[1] 傅恒志[1] 周廉[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《稀有金属材料与工程》2008年第12期2084-2088,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金重点项目(50432050)

摘　　要：采用密度泛函理论(DFT)中的BLYP和ROBLYP交换-相关泛函,基于YBa2Cu3O7单晶胞即39个原子组成的团簇模型,计算了其能隙、磁化系数、电子比热及比热系数随温度的变化关系,并分析了在不同温度下其最高占据态的分子轨道图。结果表明,YBa2Cu3O7存在3个特征温度Tc、T*和T0,在正常态存在赝能隙,并且其超导能隙和赝能隙均具有d波对称性。The energy gap, susceptibility, electronic specific heat and its coefficient in YBa2Cu3O7 have been calculated with BLYP and ROBLYP exchange-correlation function in density functional theory on a cluster model of unit cell of 39 atoms. The 3 dimension figures of HOMO at different temperature have been calculated with Gauss-View. The results show that there are 3 characteristic temperature： Tc, T^＊ and T^0 in YBa2Cu3O7. Pseudogap has been found in the normal state. Superconducting energy gap and pseudogap are d-wave symmetry.

关 键 词：密度泛函 YBA2CU3O7 磁化系数 电子比热容 电子比热系数 能隙 

分 类 号：TH142.8[一般工业技术—材料科学与工程] TM26[机械工程—机械制造及自动化]