Magnetism and Superconductivity in the t–J Model of La_(3)Ni_(2)O_7 Under Multiband Gutzwiller Approximation  

作　　者：薛洁然 王垡 Jie-Ran Xue;Fa Wang(International Center for Quantum Materials,School of Physics,Peking University,Beijing 100871,China;Collaborative Innovation Center of Quantum Matter,Beijing 100871,China)

机构地区：[1]International Center for Quantum Materials,School of Physics,Peking University,Beijing 100871,China [2]Collaborative Innovation Center of Quantum Matter,Beijing 100871,China

出　　处：《Chinese Physics Letters》2024年第5期97-106,共10页中国物理快报（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 12274004 and 11888101)。

摘　　要：The recent discovery of possible high temperature superconductivity in single crystals of La_(3)Ni_(2)O_(7) under pressure renews the interest in research on nickelates.The density functional theory calculations reveal that both d_(z^(2)) and d_(x^(2)-y^(2)) orbitals are active,which suggests a minimal two-orbital model to capture the low-energy physics of this system.In this work,we study a bilayer two-orbital t–J model within multiband Gutzwiller approximation,and discuss the magnetism as well as the superconductivity over a wide range of the hole doping.Owing to the inter-orbital super-exchange process between d_(z^(2)) and d_(x^(2)-y^(2)) orbitals,the induced ferromagnetic coupling within layers competes with the conventional antiferromagnetic coupling,and leads to complicated hole doping dependence for the magnetic properties in the system.With increasing hole doping,the system transfers to A-type antiferromagnetic state from the starting G-type antiferromagnetic(G-AFM)state.We also find the inter-layer superconducting pairing of d_(x^(2)-y^(2)) orbitals dominates due to the large hopping parameter ofd_(z^(2)) along the vertical inter-layer bonds and significant Hund’s coupling between d_(z^(2)) and d_(x^(2)-y^(2)) orbitals.Meanwhile,the G-AFM state and superconductivity state can coexist in the low hole doping regime.To take account of the pressure,we also analyze the impacts of inter-layer hopping amplitude on the system properties.

关 键 词：PROPERTIES DOPING ORBITAL 

分 类 号：O511.3[一般工业技术—材料科学与工程]