Nondegenerate valleys in the half-metallic ferromagnet Fe/WS

Article

关键词: MOS2;    SPIN;    OPTOELECTRONICS;    ELECTRONICS;    SURFACE;    WSE2;   

DOI  :  10.1103/PhysRevB.97.035404

来源: SCIE

【 摘 要 】

We present a first-principles investigation of the electronic properties of monolayer WS2 coated with an overlayer of Fe. Our ab initio calculations reveal that the system is a half-metallic ferromagnet with a gap of similar to 1 eV for the majority spin channel. Furthermore, the combined effect of time-reversal symmetry breaking due to the magnetic Fe overlayer and the large spin-orbit coupling induced by W gives rise to nondegenerate K and K' valleys. This has a tremendous impact on the excited-state properties induced by externally applied circularly polarized light. Our analysis demonstrates that the latter induces a singular hot-spot structure of the transition probability around the K and K' valleys for right and left circular polarization, respectively. We trace back the emergence of this remarkable effect to the strong momentum dependent spin-noncollinearity of the valence band involved. As a main consequence, a strong valley-selective magnetic circular dichroism is obtained, making this system a prime candidate for spintronics and photonics applications.

【 授权许可】

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