Surface-Tension-Induced Phase Transitions in Freestanding Ferroelectric Thin Films

Abstract

The control of ferroelectric topological phases in ultrathin films is central to the development of next-generation nanoelectronic devices. While epitaxial strain is widely used to tune polarization states, its applicability is inherently limited to substrate-bound systems. Here, we show that surface tension becomes a key mechanical factor in freestanding ferroelectric films, governing phase stability and the emergence of topological polarization textures. Using a thermodynamic free energy framework, we show that surface tension induces effective compressive stress in freestanding films, strongly influencing both uniform and topological polarization states. Surface tension also drives largescale morphological instabilities, reshaping phase behavior in the ferroelectric regime. Our results reveal surface tension as a robust, substrate-independent mechanism for engineering polarization states in freestanding films, creating new opportunities for flexible, strain-free ferroelectric devices.