Monolayer NbF:a 4d-analogue of cuprates  

单层NbF4:一种跟铜氧高温超导体相类似的4d^1化合物

作　　者：Yang Yang Wan-Sheng Wang Chin-Sen Ting Qiang-Hua Wang 杨阳;王万胜;丁秦生;王强华(Texas Center for Superconductivity and Department of Physics,University of Houston,Houston TX77204,USA;College of Physics and Electronic Engineering,Zhengzhou University of Light Industry,Zhengzhou 450002,China;Department of Physics,Ningbo University,Ningbo 315211,China;National Laboratory of Solid State Microstructures&School of Physics,Nanjing University,Nanjing 210093,China;Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China)

机构地区：[1]Texas Center for Superconductivity and Department of Physics,University of Houston,Houston TX77204,USA [2]College of Physics and Electronic Engineering,Zhengzhou University of Light Industry,Zhengzhou 450002,China [3]Department of Physics,Ningbo University,Ningbo 315211,China [4]National Laboratory of Solid State Microstructures&School of Physics,Nanjing University,Nanjing 210093,China [5]Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China

出　　处：《Science Bulletin》2020年第22期1901-1906,M0004,共7页科学通报（英文版）

基　　金：the National Key Research and Development Program of China(2016YFA0300401);the National Natural Science Foundation of China(11604303,11604168 and 11574134);the Texas Center for Superconductivity at the University of Houston and the Robert A.Welch Foundation(E-1146);the support from China Scholarship Council(201909440001)。

摘　　要：The electronic structure and possible electronic orders in monolayer NbF4 are investigated by density functional theory and functional renormalization group.Because of the niobium-centered octahedra,the energy band near the Fermi level is found to derive from the 4 dxyorbital,well separated from the other bands.Local Coulomb interaction drives the undoped system into an antiferromagnetic insulator.Upon suitable electron/hole doping,the system is found to develop dx2à-y2 wave superconductivity with sizable transition temperature.Therefore,the monolayer NbF4 may be an exciting 4d1 analogue of cuprates,providing a new two-dimensional platform for high-Tc superconductivity.密度泛函(DFT)以及奇异模泛函重整化群(SMFRG)等结果显示单层NbF4可能是4d1电子构型的铜氧高温超导体类似化合物,可以预想它也可以实现非常规超导.单层NbF4具有同铜氧面相类似的晶体结构.DFT结果显示单层NbF4具有4d1电子构型,即单个电子位于Nb-4dxy轨道上.类比于铜氧化物,单个能带穿过费米能级形成类似四方形的费米面结构.基于Nb-4dxy的单轨道紧束缚模型,SMFRG计算分析了电子相互作用下体系的磁有序及超导现象.结果显示在半满(电子占据数n=1.0)时,体系最终(π,π)自旋密度波通道发散,意味此时体系形成G类型反铁磁序,正好与密度泛函的结果一致.在偏离半满时,体系超导通道最终发散,其超导配对对称性显示为d波超导.单层NbF4的磁性及超导性质跟铜氧化物相似,这是由相似的晶体及电子结构导致的结果.

关 键 词：CUPRATES Two-dimensional superconductors d-wave pairing Electronic structure calculations 

分 类 号：TQ135.12[化学工程—无机化工]