Topographic patterning in perovskite oxide membranes for local control of strain, nanomechanics and electronic structure

TL;DR

This study demonstrates how controlled topographic patterning in perovskite oxide membranes induces local strains and symmetry transformations, enabling tunable electronic and structural properties for advanced device applications.

Contribution

It introduces a method to fabricate sinusoidal wrinkles in La0.7Sr0.3MnO3 membranes, controlling strain and electronic states via thickness-dependent topography.

Findings

Wrinkle morphology varies with membrane thickness, affecting stiffness and strain.

Extreme local strains (>5%) induce symmetry changes and polar distortions.

Thickness influences Mn oxidation state, indicating electronic transitions.

Abstract

Single-crystalline perovskite oxide membranes provide a powerful platform to access physical properties that are inaccessible in bulk crystals and substrate-clamped thin films. Within this context, the deliberate fabrication of tailored corrugations provides a reliable mean to impose local curvature enabling deterministic modulation of functional properties. Here, we demonstrate controlled topographic patterning in (00l)-oriented La$_{0.7}$Sr$_{0.3}$MnO$_3$ (LSMO) membranes with thicknesses ranging from 4 to 100 nm where they spontaneously form sinusoidal wrinkles with thickness-dependent periodicity and amplitude. The wrinkle morphology directly modulates membrane stiffness and generates exceptionally large local strains exceeding 5\% with strain gradients approaching $\sim$ 2.5 x 10$^{7}$ m$^{-1}$ in the thinnest membranes. These extreme deformations suppress antiferrodistortive octahedral rotations and stabilize polar distortions, evidencing a curvature-driven symmetry transformation. The surface potential variation reinforces the formation of wrinkled-induced polar patterns being strongly modulated with thickness. The variation of Mn oxidation state from $\sim$ 3.2+ to $\sim$ 2.85+ provides a direct chemical signature of a thickness-controlled electronic transition. These results demonstrate that corrugation-induced strain gradients in oxide membranes with different thicknesses can drive coupled structural, nanomechanical and electronic transformations, offering a singular route to engineer their functional states for next-generation electronic devices.