Electronic structure and magnetism of the Hund's insulator CrI3

Article

关键词: SPIN-WAVE;    FERROMAGNETISM;    RESONANCE;    CRYSTAL;   

DOI  :  10.1103/PhysRevB.105.165127

来源: SCIE

【 摘 要 】

CrI3 is a two-dimensional ferromagnetic (FM) van der Waals material with a charge gap of 1.1-1.2 eV. In this paper, the electronic structure and magnetism of CrI3 are investigated by using density functional theory and dynamical mean-field theory. Our calculations successfully reproduce a charge gap of similar to 1.1 eV in the paramagnetic (PM) state when a Hund's coupling J(H) = 0.7 eV is included with an onsite Hubbard U = 5 eV. In contrast, with a large U value of 8 eV and negligible Hund's coupling J(H), CrI3 is predicted to be a moderately correlated metal in the PM state. We conclude that CrI3 is a Mott-Hund's insulator due to the half-filled configuration of the Cr 3d t(2g) orbitals. The Cr 3d e(g) orbitals are occupied by similar to 1 electron, which leads to strong valence fluctuations so that the Cr 3d orbitals cannot be described by a single state. Moreover, at finite temperature, the calculated ordered static magnetic moment in the FM state is significantly larger in the R (3) over bar phase than in the C2/m phase. This observation indicates that the structural phase transition from the C2/m phase to the R (3) over bar phase with decreasing temperature is driven by FM spin fluctuations.

【 授权许可】

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