Sliding Ferroelectric Manipulation of Nonvolatile Ferrovalley Polarization in Parallel‐Stacked Room‐Temperature Multiferroic Homobilayers

Abstract Achieving reversible ferroelectric control over native valley polarization under ambient conditions is of extreme significance for both fundamental physics and information technology, yet such theoretical and experimental breakthroughs have not been made thus far. Here, from first‐principles and Monte Carlo simulations it is first manifested that the synthesizable RuO 2 (SiN) 2 hexagonal monolayer in experimentally reachable strain regime always behaves as an ideal ferrovalley semiconductor, rarely characterized by both robust out‐of‐plane ferromagnetism and nonvolatile switchable valley polarization simultaneously above room‐temperature. More excitingly, its parallel‐stacked A ‐type antiferromagnetic ground state generates out‐of‐plane ferroelectricity due to interlayer charge transfer, whose polarity can be inverted by lateral rigid sliding with an ultralow switching barrier. In resulting above‐room‐temperature multiferroics, the flip of ferroelectric polarization under a short‐term pulse voltage enables nonvolatile switchability of sizable valley polarization, which lays a solid foundation for the commercialization of high‐efficient post‐Moore era's multifunctional nanoelectronics. Our k · p model analysis not only captures this overall scenario but also largely expands both monolayer ferrovalley candidates isoelectronic to RuO 2 (SiN) 2 and resultant sliding multiferroic family due to numerous choices of constituent metal and ligand elements.