Sliding Ferroelectric Metals: An Emerging Frontier

Sliding ferroelectric (FE) metals have emerged as a distinct paradigm in which interlayer sliding enables switchable out-of-plane polarization in a metallic state, overcoming the conventional incompatibility between FE switching and metallicity. This Perspective traces the development of this field from its foundation in nonmagnetic systems, including 1T'-WTe₂ and T_d-MoTe₂, in which switchable polarization coexists with metallic electronic states and enables Berry curvature memory and electrically controlled superconductivity. Recent extensions to systems hosting compensated magnetic orders are also discussed. Representative material platforms further reveal that these magnetic sliding FE metals can host triply-coupled switching, sizable linear magnetoelectric coupling, and electrically tunable anomalous transport properties. Critical challenges to translating these advances into practical applications are further identified, encompassing material discovery, experimental verification of triply-coupled switching, and the development of spintronic devices.