title: Concepts of ferrovalley material and anomalous valley Hall effect.
abstract: Valleytronics rooted in the valley degree of freedom is of both theoretical and technological importance as it offers additional opportunities for information storage, as well as electronic, magnetic and optical switches. In analogy to ferroelectric materials with spontaneous charge polarization, or ferromagnetic materials with spontaneous spin polarization, here we introduce a new member of ferroic family, that is, a ferrovalley material with spontaneous valley polarization. Combining a two-band k·p model with first-principles calculations, we show that 2H-VSe2monolayer, where the spin-orbit coupling coexists with the intrinsic exchange interaction of transition-metal d electrons, is such a room-temperature ferrovalley material. We further predict that such system could demonstrate many distinctive properties, for example, chirality-dependent optical band gap and, more interestingly, anomalous valley Hall effect. On account of the latter, functional devices based on ferrovalley materials, such as valley-based nonvolatile random access memory and valley filter, are contemplated for valleytronic applications.
authors.affiliation: Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai, 200241, China.
authors.forename: Wen-Yi
authors.initials: WY
authors.lastname: Tong
authors.affiliation: Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai, 200241, China.
authors.forename: Shi-Jing
authors.initials: SJ
authors.lastname: Gong
authors.affiliation: National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, Jiangsu 210093, China.|Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, China.
authors.forename: Xiangang
authors.initials: X
authors.lastname: Wan
authors.affiliation: Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai, 200241, China.|Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China.
authors.forename: Chun-Gang
authors.initials: CG
authors.lastname: Duan