A phononic switch based on ferroelectric domain walls

TL;DR

This study demonstrates that ferroelectric domain walls in PbTiO3 can be used to create a tunable phononic switch by modulating heat flux through their thermal boundary resistance, with potential for dynamic thermal management.

Contribution

The paper provides a detailed numerical analysis of the thermal boundary resistance of ferroelectric domain walls, establishing their potential for electrically controlled phononic switching devices.

Findings

Thermal boundary resistance increases by up to 20% due to a single domain wall.

Excellent agreement between molecular dynamics and Green's functions methods.

Multiple domain walls can further enhance thermal resistance.

Abstract

The ease with which domain walls (DWs) in ferroelectric materials can be written and erased provides a versatile way to dynamically modulate heat fluxes. In this work we evaluate the thermal boundary resistance (TBR) of 180$^{\circ}$ DWs in prototype ferroelectric perovskite PbTiO$_3$ within the numerical formalisms of nonequilibrium molecular dynamics and nonequilibrium Green's functions. An excellent agreement is obtained for the TBR of an isolated DW derived from both approaches, which reveals the harmonic character of the phonon-DW scattering mechanism. The thermal resistance of the ferroelectric material is shown to increase up to around 20%, in the system sizes here considered, due to the presence of a single DW, and larger resistances can be attained by incorporation of more DWs along the path of thermal flux. These results, obtained at device operation temperatures, prove the viability of an electrically actuated phononic switch based on ferroelectric DWs.