Sliding-mediated ferroelectric phase transition in CuInP2S6 under pressure

Abstract

Interlayer stacking order has recently emerged as a unique degree of freedom to control crystal symmetry and physical properties in two-dimensional van der Waals (vdW) materials and heterostructures. By tuning the layer stacking pattern, symmetry-breaking and electric polarization can be created in otherwise non-polar crystals, whose polarization reversal depends on the interlayer sliding motion. Herein, we demonstrate that in a vdW layered ferroelectric, its existing polarization is closely coupled to the interlayer sliding driven by hydrostatic pressure. Through combined structural, electrical, vibrational characterizations, and theoretical calculations, we clearly map out the structural evolution of CuInP2S6 under pressure. A tendency towards a high polarization state is observed in the low-pressure region, followed by an interlayer-sliding-mediated phase transition from a monoclinic to a trigonal phase. Along the transformation pathway, the displacive-instable Cu ion serves as a pivot point that regulates the interlayer interaction in response to external pressure. The rich phase diagram of CuInP2S6, which is enabled by stacking orders, sheds light on the physics of vdW ferroelectricity and opens an alternative route to tailoring long-range order in vdW layered crystals.

arXiv comment22 pages, 4 figures

References in corpus (10)

• Stacking-engineered ferroelectricity in bilayer boron nitride
• Interfacial Ferroelectricity by van-der-Waals Sliding
• Sliding induced multiple polarization states in two-dimensional ferroelectrics
• Cumulative Polarization Coexisting with Conductivity at Interfacial Ferroelectrics
• Structural and electronic phase transitions in FePS${}_3$ under the application of pressure
• Giant negative electrostriction and dielectric tunability in a van der Waals layered ferroelectric
• Evolution of magnetic order in van-der-Waals antiferromagnet FePS${}_3$ through insulator-metal transition
• Ionic control over ferroelectricity in 2D layered van der Waals capacitors
• Vibrational properties of CuInP2S6 across the ferroelectric transition
• Pressure-Induced Insulator-to-Metal Transition in van der Waals compound CoPS${}_3$

Cited by in corpus (1)

• Deciphering the lattice vibrational behaviors of CuInP2S6 by angle-resolved polarized Raman scattering