Effects of the substrate-surface reconstruction and orientation on the spin valley polarization in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>Mo</mml:mi><mml:msub><mml:mi>Te</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:mo>/</mml:mo><mml:mi>Eu</mml:mi><mml:mi mathvariant="normal">O</mml:mi></mml:mrow></mml:math>
Ao Zhang, Zisheng Gong, Ziming Zhu, Anlian Pan, Mingxing Chen
Abstract
We investigate the spin valley polarization in $\mathrm{Mo}{\mathrm{Te}}_{2}$ monolayer on (111) and (001) surfaces of ferromagnetic semiconductor EuO based on first-principles calculations. We consider surface reconstructions for EuO(111). We find that there is no direct chemical bonding between the reconstructed EuO(111) and the $\mathrm{Mo}{\mathrm{Te}}_{2}$ overlayer, in contrast to the case of the ideal EuO(111). However, there is a strong hybridization between the states of $\mathrm{Mo}{\mathrm{Te}}_{2}$ and the substrate states, which has a substantial impact on the valleys. The valley polarization due to the magnetic proximity effect is dependent on the detail of the interface structure, which is in the range of a few meV to about 40 meV. These values are at least one order of magnitude smaller than that induced by the ideal EuO(111). When the $\mathrm{Mo}{\mathrm{Te}}_{2}$ monolayer is interfaced with EuO(001), the valley polarization is about 3.2 meV, insensitive to the interface structure. By a low-energy effective Hamiltonian model, the effective Zeeman field induced by EuO(001) is about 27 T, comparable to that for $\mathrm{W}{\mathrm{Se}}_{2}/\mathrm{Eu}\mathrm{S}$ obtained by experiment.