Abstract
We present a first-principles investigation of the electronic properties of monolayer coated with an overlayer of Fe. Our ab initio calculations reveal that the system is a half-metallic ferromagnet with a gap of 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 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 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.
- Received 11 October 2017
- Revised 18 December 2017
DOI:https://doi.org/10.1103/PhysRevB.97.035404
©2018 American Physical Society