Observation of Spin‐Induced Ferroelectricity in a Layered van der Waals Antiferromagnet CuCrP2S6

Abstract

AbstractCuCrP2S6, a van der Waals magnet having stacked layers of 2D honeycomb lattice made of CuS3 triangles and CrS6 octahedra, exhibits an A‐type antiferromagnetic order with the Néel temperature (TN) = 32 K. Upon in‐plane magnetic field (H) being applied below TN, H‐induced modulation of the c*‐axis electric polarization (ΔPc*) is found at fields lower than the saturation field µ0HS = 6.1 T, at which a forced ferromagnetic alignment sets in. Based on the symmetry analyses and dependence of ΔPc* on H and the azimuthal angle of applied H direction, a microscopic origin of the magnetoelectric (ME) coupling is attributed to the spin‐direction‐dependent p–d hybridization that is allowed due to the presence of off‐centered Cr3+ octahedra. A comparative study on CuCrP2Se6, however, finds no H‐induced P modulation due to cancellation of P between neighboring layers with the doubling of a crystallographic unit cell at TN. As the p–d hybridization mechanism allows generation of P in a single Cr atom–ligand pair, the results imply that large ME coupling should exist even in a single layer limit of CuCrP2S6.