Universal Dimensionality of Ferroelectric Domain Walls in Ultrathin Films

Abstract

The dimensionality of dynamic interfaces—domain walls (DWs) —is greatly influenced by symmetry and physical dimensions, irrespective of the microscopic details of the system. To address this fundamental question for the ferroelectric model system, the DW scaling criticality and dimensionality is investigated in ultrathin films of varied ferroelectric materials, compositions, and electrode–ferroelectric interfaces, grown on nominally flat and vicinal substrates. In spite of significant variations among ferroelectric systems, the observed prevalence of 1D DWs is consistent with a random bond disorder, elucidated through a scenario of 2D nucleation and growth-driven DW creep. These findings highlight the thickness size-dominated universal behavior of ferroelectric DWs, uncovering fascinating prospects for dimensionally engineered DW-based nanoelectronics.