Effect of Rare-Earth Element Substitution in Superconducting R_(3)Ni_(2)O_(7) under Pressure  

作　　者：Zhiming Pan Chen Lu Fan Yang Congjun Wu 潘志明;卢晨;杨帆;吴从军(Institute for Theoretical Sciences,Westlake University,Hangzhou 310024,China;New Cornerstone Science Laboratory,Department of Physics,School of Science,Westlake University,Hangzhou 310024,China;School of Physics,Beijing Institute of Technology,Beijing 100081,China;Key Laboratory for Quantum Materials of Zhejiang Province,School of Science,Westlake University,Hangzhou 310024,China;Institute of Natural Sciences,Westlake Institute for Advanced Study,Hangzhou 310024,China)

机构地区：[1]Institute for Theoretical Sciences,Westlake University,Hangzhou 310024,China [2]New Cornerstone Science Laboratory,Department of Physics,School of Science,Westlake University,Hangzhou 310024,China [3]School of Physics,Beijing Institute of Technology,Beijing 100081,China [4]Key Laboratory for Quantum Materials of Zhejiang Province,School of Science,Westlake University,Hangzhou 310024,China [5]Institute of Natural Sciences,Westlake Institute for Advanced Study,Hangzhou 310024,China

出　　处：《Chinese Physics Letters》2024年第8期77-81,共5页中国物理快报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.12234016,12174317,and 12074031);the New Cornerstone Science Foundation.

摘　　要：Recently,high temperature(T_(c)≈80 K)superconductivity(SC)has been discovered in La_(3)Ni_(2)O_(7)(LNO)under pressure.This raises the question of whether the superconducting transition temperature T_(c) could be further enhanced under suitable conditions.One possible route for achieving higher T_(c) is element substitution.Similar SC could appear in the Fmmm phase of rare-earth(RE)R_(3)Ni_(2)O_(7)(RNO,R=RE element)material series under suitable pressure.The electronic properties in the RNO materials are dominated by the Ni 3d orbitals in the bilayer NiO_(2) plane.In the strong coupling limit,the SC could be fully characterized by a bilayer single 3d_(x^(2)−y^(2))-orbital t–J‖–J⊥ model.With RE element substitution from La to other RE element,the lattice constant of the Fmmm RNO material decreases,and the resultant electronic hopping integral increases,leading to stronger superexchanges between the 3d_(x^(2)−y^(2)) orbitals.Based on the slave-boson mean-field theory,we explore the pairing nature and the evolution of T_(c) in RNO materials under pressure.Consequently,it is found that the element substitution does not alter the pairing nature,i.e.,the inter-layer s-wave pairing is always favored in the superconducting RNO under pressure.However,the T_(c) increases from La to Sm,and a nearly doubled T_(c) could be realized in SmNO under pressure.This work provides evidence for possible higher T_(c) R_(3)Ni_(2)O_(7) materials,which may be realized in further experiments.

关 键 词：ELEMENT SUBSTITUTION RARE 

分 类 号：O469[理学—凝聚态物理]