September 2023

Journal

Layered Semiconductor Cr0.32Ga0.68Te2.33 with Concurrent Broken Inversion Symmetry and Ferromagnetism: A Bulk Ferrovalley Material Candidate

By:
Guan, Yingdong; Miao, Leixin; He, Jingyang; Ning, Jinliang; Chen, Yangyang; Xie, Weiwei; Sun, Jianwei; Gopalan, Venkatraman; Zhu, Jun; Wang, Xiaoping ; Alem, Nasim; Zhang, Qiang ; Mao, Zhiqiang
Journal Name:
Journal of the American Chemical Society
Page Number:
4683-4690
Volume:
145
Issue Number:
8
Publication Date:
September 2023
View DOI Listing:
https://doi.org/10.1021/jacs.2c12848

Abstract

The valleytronic state found in group-VI transition-metal dichalcogenides such as MoS2 has attracted immense interest since its valley degree of freedom could be used as an information carrier. However, valleytronic applications require spontaneous valley polarization. Such an electronic state is predicted to be accessible in a new ferroic family of materials, i.e., ferrovalley materials, which features the coexistence of spontaneous spin and valley polarization. Although many atomic monolayer materials with hexagonal lattices have been predicted to be ferrovalley materials, no bulk ferrovalley material candidates have been reported or proposed. Here, we show that a new non-centrosymmetric van der Waals (vdW) semiconductor Cr0.32Ga0.68Te2.33, with intrinsic ferromagnetism, is a possible candidate for bulk ferrovalley material. This material exhibits several remarkable characteristics: (i) it forms a natural heterostructure between vdW gaps, a quasi-two-dimensional (2D) semiconducting Te layer with a honeycomb lattice stacked on the 2D ferromagnetic slab comprised of the (Cr, Ga)-Te layers, and (ii) the 2D Te honeycomb lattice yields a valley-like electronic structure near the Fermi level, which, in combination with inversion symmetry breaking, ferromagnetism, and strong spin-orbit coupling contributed by heavy Te element, creates a possible bulk spin-valley locked electronic state with valley polarization as suggested by our DFT calculations. Further, this material can also be easily exfoliated to 2D atomically thin layers. Therefore, this material offers a unique platform to explore the physics of valleytronic states with spontaneous spin and valley polarization in both bulk and 2D atomic crystals.


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