Deconvolution of Phonon Scattering by Ferroelectric Domain Walls and Point Defects in a PbTiO 3 Thin Film Deposited in a Composition-Spread Geometry

• DOI: 10.48550/arxiv.2104.14494
• Publication Date: 2021-09-15
• Authors: Elías Ferreiro-Vila; Neus Domingo; Darrell G. Schlom; Darrell G. Schlom; Eric Langenberg; Eric Langenberg; Eric Langenberg; Gustau Catalan; Xavier Batlle; Christina Stefani; Eva H. Smith; Francisco Rivadulla; David Bugallo
• Keywords: Ferroelectrics; Condensed Matter - Materials Science; Materials Science (cond-mat.mtrl-sci); FOS: Physical sciences; Composition-spread combinatorial study; 02 engineering and technology; Domain walls; Mathematical methods; Thermal conductivity; Polarization; Phonons; Defects; 0210 nano-technology; Phonon-scattering mechanisms

We present a detailed analysis of the temperature dependence of the thermal conductivity of a ferroelectric PbTiO3 thin film deposited in a composition-spread geometry enabling a continuous range of compositions from ~25% titanium-deficient to ~20% titanium-rich to be studied. By fitting the experimental results to the Debye model we deconvolve and quantify the two main phonon scattering sources in the system: ferroelectric domain walls (DWs) and point defects. Our results prove that ferroelectric DWs are the main agent limiting the thermal conductivity in this system, not only in the stoichiometric region of the thin film ([Pb]/[Ti]~1), but also when the concentration of cation point defects is significant (up to ~15%). Hence, DWs in ferroelectric materials are a source of phonon scattering at least as effective as point defects. Our results demonstrate the viability and effectiveness of using reconfigurable DWs to control the thermal conductivity in solid-state devices.