Phase-Dependent Magnetic Proximity Modulations on Valley Polarization and Splitting.

Li, Jin'an; Chen, Zilong; Zhou, Jiangpeng; Zhang, Yiteng; Li, Xu; Wu, Zhiming; Wu, Yaping; Kang, Junyong · ACS Nano · 2024

basic_science · Level V

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Abstract

Proximate-induced magnetic interactions present a promising strategy for precise manipulation of valley degrees of freedom. Taking advantage of the splendid valleytronic platform of transition metal dichalcogenides, magnetic two-dimensional VSe<sub>2</sub> with different phases are introduced to intervene in the spin of electrons and modulate their valleytronic properties. When constructing the heterostructures, 1T-VSe<sub>2</sub>/WX<sub>2</sub> (X = S and Se) showcases significant improvement in the valley polarizations at room temperature, while 2H-VSe<sub>2</sub>/WX<sub>2</sub> exhibits superior performance at low temperatures and demonstrates heightened sensitivity to the external magnetic field. Simultaneously, considerable valley splitting with a large <i>g</i><sub>eff</sub> factor up to -29.0 is observed in 2H-VSe<sub>2</sub>/WS<sub>2</sub>, while it is negligible in 1T-VSe<sub>2</sub>/WX<sub>2</sub>. First-principles calculations reveal a phase-dependent magnetic proximity mechanism on the valleytronic modulations, which is dominated by interfacial charge transfer in 1T-VSe<sub>2</sub>/WX<sub>2</sub> and the proximity exchange field in 2H-VSe<sub>2</sub>/WX<sub>2</sub> heterostructures. The effective control over valley degrees of freedom will bridge the valleytronic physics and devices, rendering enormous potential in the field of valley quantum applications.