Thermal transport manipulated by vortex domain walls in bulk h-ErMnO3

Topological defects such as structural vortex domain walls (DWs), which induce many intriguing properties and associated physical phenomena in multiferroics, also provide a platform for manipulating thermal transport. Here, we employ time-domain thermoreflectance (TDTR) to study the thermal conductivity of bulk h-ErMnO3 single crystals with different vortex DWs over a wide temperature range. We find that the vortex DWs can effectively and synergistically suppress the thermal conductivity along (cc) and perpendicular (cab) to the c-axis of h-ErMnO3 single crystals. A phonon scattering model is utilized to explain the mechanism of thermal transport manipulated by vortex DWs. This model yields the intrinsic thermal conductivity and the effective phonon mean free path (MFP) of h-ErMnO3. The model also manifests that vortex DWs achieve a maximum reduction of similar to 28% for the room-temperature thermal conductivity against the single-domain case. The reduction becomes more significant with decreasing temperature due to the longer effective MFP at lower temperatures, both proved experimentally by the cryogenic experiment and theoretically based on the proposed phonon scattering model. These findings not only provide an essential understanding of heat transport in multiferroics with vortex DWs but also pave the way for their application in next-generation ferroelectric devices.

Automated summary

In this study, the thermal conductivity of h-ErMnO3 single crystals with different vortex domain walls (DWs) was investigated using time-domain thermoreflectance (TDTR). It was found that the vortex DWs can effectively suppress the thermal conductivity along and perpendicular to the c-axis of the crystals. A phonon scattering model was used to explain the mechanism of thermal transport manipulated by the vortex DWs. These findings not only provide an essential understanding of heat transport in multiferroics with vortex DWs but also pave the way for their application in next-generation ferroelectric devices.