Dataset for "Direct Thermal Imaging of Domain Wall Hot Spots in LiNbO3"

This is the dataset associated with the publication: Lindsey R Lynch et al. "Direct Thermal Imaging of Domain Wall Hot Spots in LiNbO3" Small, e08603, 2025 (https://doi.org/10.1002/smll.202508603).

The data files are the raw and processed outputs of Scanning Thermal Microscopy measurements used to plot the spatial maps of temperature in Figure 2,3 and 4 of the main manuscript. The files are .ibw format (a proprietary format used by Wave Metric Igor Pro software for storing scanning probe microscopy data). The file are also supplied in plain text .txt format.

Abstract
Ferroelectric domain wall devices offer a promising route to low voltage, reconfigurable nanoelectronics by confining currents to nanoscale conducting interfaces within an insulating bulk. However, the potential for resistive heating and unregulated temperature increases due to domain wall conduction remains unexplored. Here, we employ scanning thermal microscopy to directly image hot spots in thin-film lithium niobate domain wall devices. Piezoresponse force microscopy shows that the hot spots correlate with nanodomain structure and thermal mapping reveals surface temperature rises of ~ 20 K at most, levels that are unlikely to negatively affect device performance. This is due to the moderate electrical conductivity of domain walls, their voltage-tunable erasure, and distributed current pathways, which inherently limit power dissipation and peak temperatures. Finite element electrothermal modelling indicates that domain walls behave as pseudo-planar heat sources, distinct from the filament-based heating typically observed in resistive switching oxides. These findings highlight the potential for domain wall devices as an energy-efficient, thermally stable platform for emerging memory and logic applications.