Two-dimensional CoSe structures: Intrinsic magnetism, strain-tunable anisotropic valleys, magnetic Weyl point, and antiferromagnetic metal state

Article

关键词: HIGH-TEMPERATURE SUPERCONDUCTIVITY;    FESE FILMS;    MONOLAYER;    FERROMAGNETISM;    CRYSTAL;    OXIDE;   

DOI  :  10.1103/PhysRevB.102.224422

来源: SCIE

【 摘 要 】

The interplay between magnetism, band topology, and electronic correlation in low dimensions has been a fascinating subject of research. Here, we propose two-dimensional (2D) material systems which demonstrate such an interesting interplay. Based on first-principles calculations and structural search algorithms, we identify three lowest energy 2D CoSe structures, termed as the alpha-, beta-, and gamma-CoSe. We show that alpha- and beta-CoSe are two rare examples of 2D antiferromagnetic metals, which are related to their Fermi surfaces nesting features, and meanwhile, gamma-CoSe is a ferromagnetic metal. They possess a range of interesting physical properties, including anisotropic valleys connected by crystalline symmetries, strain-tunable valley polarization, strain-induced metal-semiconductor and/or magnetic phase transitions, as well as topological band features such as the magnetic Weyl point and the magnetic Weyl loop. Remarkably, all the topological features here are robust against spin-orbit coupling. Some experimental aspects of our predictions have been discussed.

【 授权许可】

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