Department of Materials Science and Engineering and Materials Research Institute , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States.
Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States.
ACS Appl Mater Interfaces. 2018 Aug 1;10(30):25493-25501. doi: 10.1021/acsami.8b04169. Epub 2018 Jul 19.
Ferroelastic domain walls in ferroelectric materials possess two properties that are known to affect phonon transport: a change in crystallographic orientation and a lattice strain. Changing populations and spacing of nanoscale-spaced ferroelastic domain walls lead to the manipulation of phonon-scattering rates, enabling the control of thermal conduction at ambient temperatures. In the present work, lead zirconate titanate (PZT) thin-film membrane structures were fabricated to reduce mechanical clamping to the substrate and enable a subsequent increase in the ferroelastic domain wall mobility. Under application of an electric field, the thermal conductivity of PZT increases abruptly at ∼100 kV/cm by ∼13% owing to a reduction in the number of phonon-scattering domain walls in the thermal conduction path. The thermal conductivity modulation is rapid, repeatable, and discrete, resulting in a bistable state or a "digital" modulation scheme. The modulation of thermal conductivity due to changes in domain wall configuration is supported by polarization-field, mechanical stiffness, and in situ microdiffraction experiments. This work opens a path toward a new means to control phonons and phonon-mediated energy in a digital manner at room temperature using only an electric field.
晶体取向的变化和晶格应变。改变纳米级间隔的铁弹畴壁的数量和间距会导致声子散射率的变化，从而实现环境温度下热传导的控制。在本工作中，制备了锆钛酸铅（PZT）薄膜结构，以减少对衬底的机械夹持，并随后提高铁弹畴壁的迁移率。在施加电场的情况下，PZT 的热导率在约 100 kV/cm 时突然增加约 13%，这是由于热传导路径中声子散射畴壁的数量减少所致。热导率的调制快速、可重复且离散，导致双稳态或“数字”调制方案。畴壁结构变化引起的热导率调制得到了极化场、机械刚度和原位微衍射实验的支持。这项工作为仅通过电场以数字方式在室温下控制声子和声子介导的能量开辟了一条新途径。
