RT Journal Article T1 Ferroelectric Domain Walls in PbTiO3 Are Effective Regulators of Heat Flow at Room Temperature A1 Langenberg Pérez, Eric A1 Saha, Dipanjan A1 Holtz, Megan E. A1 Wang, Jian-Jun A1 Bugallo Ferrón, David A1 Ferreiro Vila, Elías A1 Paik, Hanjong A1 Hanke, Isabelle A1 Ganschow, Steffen A1 Muller, David A. A1 Chen, Long-Qing A1 Catalan, Gustau A1 Domingo, Neus A1 Malen, Jonathan A1 Schlom, Darrell G. A1 Rivadulla Fernández, José Francisco K1 Epitaxial strain engineering K1 Domain walls K1 Ferroelectrics K1 Thermal conductivity K1 Thin films K1 Phononics AB Achieving efficient spatial modulation of phonon transmission is an essential step on the path to phononic circuits using “phonon currents”. With their intrinsic and reconfigurable interfaces, domain walls (DWs), ferroelectrics are alluring candidates to be harnessed as dynamic heat modulators. This paper reports the thermal conductivity of single-crystal PbTiO3 thin films over a wide variety of epitaxial-strain-engineered ferroelectric domain configurations. The phonon transport is proved to be strongly affected by the density and type of DWs, achieving a 61% reduction of the room-temperature thermal conductivity compared to the single-domain scenario. The thermal resistance across the ferroelectric DWs is obtained, revealing a very high value (≈5.0 × 10–9 K m2 W–1), comparable to grain boundaries in oxides, explaining the strong modulation of the thermal conductivity in PbTiO3. This low thermal conductance of the DWs is ascribed to the structural mismatch and polarization gradient found between the different types of domains in the PbTiO3 films, resulting in a structural inhomogeneity that extends several unit cells around the DWs. These findings demonstrate the potential of ferroelectric DWs as efficient regulators of heat flow in one single material, overcoming the complexity of multilayers systems and the uncontrolled distribution of grain boundaries, paving the way for applications in phononics PB American Chemical Society SN 1530-6984 YR 2019 FD 2019 LK http://hdl.handle.net/10347/20433 UL http://hdl.handle.net/10347/20433 LA eng NO Nano Lett. 2019, 19, 11, 7901-7907 NO This work has received financial support from Ministerio de Economía y Competitividad (Spain) under project no. MAT2016-80762-R, Xunta de Galicia (Centro singular de investigación de Galicia accreditation 2016-2019, ED431G/09), the European Union (European Regional Development Fund-ERDF), and the European Commission through the Horizon H2020 funding by H2020-MSCA-RISE-2016 project no. 734187-SPICOLOST. E.L. acknowledges the funding received from the European Union’s Horizon 2020 research and innovation program through the Marie Skłodowska-Curie Actions: Individual Fellowship-Global Fellowship (ref. MSCA-IF-GF-708129). D.B. acknowledges financial support from MINECO (Spain) through an FPI fellowship (BES-2017-079688). The work at Cornell was supported by the Army Research Office under grant W911NF-16-1-0315. H.P. acknowledges support from the National Science Foundation [Platform for the Accelerated Realization, Analysis, and Discovery of Interface Materials (PARADIM)] under cooperative agreement no. DMR-1539918 DS Minerva RD 3 may 2026