摘要
基于密度泛函理论的第一性原理计算,本文对单层1T-CoI_(2)的原子、电子结构和磁性进行了理论研究.使用广义布洛赫条件结合自旋螺旋方法计算了单层1T-CoI_(2)自旋螺旋的能量色散关系E(q),计算结果表明单层1T-CoI_(2)的基态呈现螺旋反铁磁,体系中含有键相关的各向异性作用,即Kitaev作用.计算了含有自旋-轨道耦合作用(spin orbital coupling,SOC)和不含有SOC的色散关系,分别将色散关系映射到HeisenbergKitaev模型,成功分解了多近邻海森伯作用参数J、Kitaev作用的K和非对角项Γ.单层1T-CoI_(2)以Heisenberg作用为主导,同时存在着较强的Kitaev相互作用,其中Γ_(1)达到了1.09 meV.可预测Kitaev作用在具有1T结构过渡金属三角格子中具有普遍适用性,表明单层1T-CoI_(2)是Kitaev的备选材料,并且为探索其他二维磁性材料的Kitaev作用奠定了理论基础.
Kitaev interactions,which are bond-related anisotropic interactions induced by spin-orbit coupling(SOC),may produce quantum spin liquid states in two-dimensional(2D)magnetic hexagonal lattices such as RuCl_(3).Generally,the strong SOCs in these materials come from heavy metal elements such as Ru in RuCl_(3).In recent years,some related studies have shown the presence of Kitaev effects in some 2D monolayers of ortho-octahedral structures containing heavy ligand elements,such as CrGeTe_(3)and CrSiTe_(3).However,there are relatively few reports on the Kitaev interactions in 2D monolayer 1T structures.In this paper,we calculate and analyse the atomic and electronic structures of 1T-CoI_(2)and the Kitaev interactions contained therein by the first-principles calculation program VASP.The structure of 1T-CoI_(2)is a triangular lattice with an emphasis on ES(q)=EN+S(q)-EN(q)the coordinating element I.The energy dispersion relation for the contained Kitaev EN(q)action is isolated by calculating the energy dispersion relation for the spin-spiral of monolayer CoI_(2)EN+S(q)without SOC and the energy dispersion relation considering SOC by using the generalized Bloch condition combined with the spin-spiral method.The parameters of the Heisenberg exchange interaction ES(q)induced by the SOC are obtained by fitting the dispersion law of the to the Kitaev exchange interaction with the parameters of the Kitaev exchange interaction.The fitted curves obtained with the fitted parameters are in good agreement with the calculated values,indicating the accuracy of our calculations.Calculated fits show that the monolayer CoI_(2)is dominated by Heisenberg action,with the third nearest neighbour having the largest absolute value of J at-1.81 meV.In addition to this,there are strong Kitaev interactions in the monolayer CoI_(2),whereΓ_(1)reaches 1.09 meV.We predict that the Kitaev interactions are universally applicable to transition metal triangular lattices with 1T structure.It is shown that the CoI_(2)can be used as an alternative mater
作者
朱凯
黄灿
曹邦杰
潘燕飞
樊济宇
马春兰
朱岩
Zhu Kai;Huang Can;Cao Bang-Jie;Pan Yan-Fei;Fan Ji-Yu;Ma Chun-Lan;Zhu Yan(College of Physics,Nanjing University of Aeronautics and Astronautics,Nanjing 210006,China;Key Laboratory of Aerospace Information Materials and Physics,Ministry of Industry and Information Technology,Nanjing University of Aeronautics and Astronautics,Nanjing 210006,China;Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application,School of Physical Science and Technology,Suzhou University of Science and Technology,Suzhou 215009,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2023年第24期249-257,共9页
Acta Physica Sinica