Ferroelectric Domain Walls in PbTiO<inf>3</inf> Are Effective Regulators of Heat Flow at Room Temperature

Eric Langenberg, Dipanjan Saha, Megan E. Holtz, Jian Jun Wang, David Bugallo, Elias Ferreiro-Vila, Hanjong Paik, Isabelle Hanke, Steffen Ganschow, David A. Muller, Long Qing Chen, Gustau Catalan, Neus Domingo, Jonathan Malen, Darrell G. Schlom, Francisco Rivadulla

    Research output: Contribution to journalArticleResearch

    10 Citations (Scopus)

    Abstract

    © 2019 American Chemical Society. 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.
    Original languageEnglish
    JournalNano Letters
    DOIs
    Publication statusPublished - 1 Jan 2019

    Keywords

    • Epitaxial strain engineering
    • domain walls
    • ferroelectrics
    • phononics
    • thermal conductivity
    • thin films

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