Giant Thermal Transport Tuning at a Metal/Ferroelectric Interface

Abstract

Interfacial thermal transport plays a prominent role in the thermal management of nanoscale objects and is of fundamental importance for basic research and nanodevices. At metal/insulator interfaces, a configuration commonly found in electronic devices, heat transport strongly depends upon the effective energy transfer from thermalized electrons in the metal to the phonons in the insulator. However, the mechanism of interfacial electron–phonon coupling and thermal transport at metal/insulator interfaces is not well understood. Here, the observation of a substantial enhancement of the interfacial thermal resistance and the important role of surface charges at the metal/ferroelectric interface in an Al/BiFeO3 membrane are reported. By applying uniaxial strain, the interfacial thermal resistance can be varied substantially (up to an order of magnitude), which is attributed to the renormalized interfacial electron–phonon coupling caused by the charge redistribution at the interface due to the polarization rotation. These results imply that surface charges at a metal/insulator interface can substantially enhance the interfacial electron–phonon‐mediated thermal coupling, providing a new route to optimize the thermal transport performance in next‐generation nanodevices, power electronics, and thermal logic devices.

Freestanding Perovskite Oxide Films: Synthesis, Challenges, and Properties

“…[52] The ability to manipulate the polarization direction through strain was also exploited by Zang et al to engineer the interfacial thermal resistance in self standing Al/BiFeO 3 membranes. [51] In their work, the variation of polarization direction in ferroelectric BiFeO 3 through strain gave rise to a redistribution of the charge at the interface and eventually, through electronphonon coupling, to a modification of the interface thermal resistance.…”

Freestanding complex-oxide membranes

“…For membranes of PbTiO 3 (a tetragonal FE at room temperature), a similar strategy was used to tune the domain orientation from predominantly out-of-plane to predominantly in-plane, as observed in x-ray diffraction measurements of the membranes under strain applied to the polymer substrate up to 6% [91]. For membranes of BiFeO 3 , the same polarization rotation effect under uniaxial tensile strain was used to explain the large modulation in thermal resistance across the films, as measured via the thermoreflectance technique [143]. All these works represented an advance with respect to strain engineering in epitaxial films in that uniaxial strain (instead of biaxial) can be used, providing a maximum achievable strain that is 2-3 times larger than typical values in epitaxial films and the strain tunability is 1-2 orders of magnitude larger than that achievable via piezoelectric substrates [141], thus providing an excellent tool for manipulating structures and tuning electronic correlations to a large extent.…”

Advanced Epitaxial Lift‐Off and Transfer Procedure for the Fabrication of High‐Quality Functional Oxide Membranes

“…Polydimethylsiloxane (PDMS) adhesive has been extensively used, [18,20,22,25,39] but it is sometimes replaced by photo resists, [27,33,36] tapes (polyimide tapes like Kapton or thermal release tapes), [29,34,36] or epoxy glue. [40] Membrane transfer strategies without the use of adhesives also exist, like the so-called "fishing" method, [31,37,41] or the more recently developed procedure by Sambri et al which does not use any sacrificial layer. [42] Most membrane lift-off and transfer methods used up to date have been at least partially inspired by the developed In the past 5 years, the transfer of epitaxial oxide thin films has drawn a renewed interest in the scientific community.…”