Sr-Doping-Modulated Metal-Insulator Transition in NdNiO_(3) Epitaxial Films  

作　　者：Huan Ye Enda Hua Fang Xu Jingdi Lu Feng Jin Wenbin Wu Liang,Si Lingfei Wang 叶欢;华恩达;许方;鲁京迪;金锋;吴文彬;司良;王凌飞(Hefei National Research Center for Physical Sciences at Microscale,University of Science and Technology of China,Hefei 230026,China;School of Physics,Northwest University,Xi’an 710127,China)

机构地区：[1]Hefei National Research Center for Physical Sciences at Microscale,University of Science and Technology of China,Hefei 230026,China [2]School of Physics,Northwest University,Xi’an 710127,China

出　　处：《Chinese Physics Letters》2024年第11期99-113,共15页中国物理快报（英文版）

基　　金：supported by the National Key Research and Development Program of China(Grant Nos.2023YFA1406404 and 2020YFA0309100);the National Natural Science Foundation of China(Grant Nos.12074365,12374094,12304153,U2032218,and 11974326),the National Natural Science Foundation of China(Grant No.12274120);CAS Project for Young Scientists in Basic Research(Grant No.YSBR-084);the Fundamental Research Funds for the Central Universities(Grant Nos.WK9990000102 and WK2030000035);Anhui Provincial Natural Science Foundation(Grant No.2308085MA15);Hefei Science Center CAS Foundation(Grant Nos.2021HSC-CIP017 and 2016HSC-IU06);the China Postdoctoral Science Foundation(Grant No.2022M713060);the starting funds from Northwest University;support from the Vienna Scientific Cluster(VSC)for the first-principles calculations。

摘　　要：Perovskite-structured nickelates,ReNiO_(3)(Re=rare earth),have long garnered significant research interest due to their sharp and highly tunable metal-insulator transitions(MITs).Doping the parent compound ReNiO_(3)with alkaline earth metal can substantially suppress this MIT.Recently,intriguing superconductivity has been discovered in doped infinite-layer nickelates(ReNiO_(2)),while the mechanism behind A-site doping-suppressed MIT in the parent compound ReNiO_(3)remains unclear.To address this problem,we grew a series of Nd_(1−x)Sr_(x)NiO_(3)(NSNO,x=0–0.2)thin films and conducted systematic electrical transport measurements.Our resistivity and Hall measurements suggest that Sr-induced excessive holes are not the primary reason for MIT suppression.Instead,first-principles calculations indicate that Sr cations,with larger ionic radius,suppress breathing mode distortions and promote charge transfer between oxygen and Ni cations.This process weakens Ni–O bond disproportionation and Ni^(2+)/Ni^(4+)charge disproportionation.Such significant modulations in lattice and electronic structures convert the ground state from a charge-disproportionated antiferromagnetic insulator to a paramagnetic metal,thereby suppressing the MIT.This scenario is further supported by the weakened MIT observed in the tensile-strained NSNO/SrTiO_(3)(001)films.Our work reveals the A-side doping-modulated electrical transport of perovskite nickelate films,providing deeper insights into novel electric phases in these strongly correlated nickelate systems.

关 键 词：DOPING NICKEL EARTH 

分 类 号：O469[理学—凝聚态物理]