  Antiferromagnetic order, being a ground state of a number of exotic quantum
materials, is of immense interest both from the fundamental physics perspective
and for driving potential technological applications. For a complete
understanding of antiferromagnetism in materials, nanoscale visualization of
antiferromagnetic domains, domain walls and their robustness to external
perturbations is highly desirable. Here, we synthesize antiferromagnetic FeTe
thin films using molecular beam epitaxy. We visualize local antiferromagnetic
ordering and domain formation using spin-polarized scanning tunneling
microscopy. From the atomically-resolved scanning tunneling microscopy
topographs, we calculate local structural distortions to find a high
correlation with the distribution of the antiferromagnetic order. This is
consistent with the monoclinic structure in the antiferromagnetic state.
Interestingly, we observe a substantial domain wall change by small temperature
variations, unexpected for the low temperature changes used compared to the
much higher antiferromagnetic ordering temperature of FeTe. This is in contrast
to electronic nematic domains in the cousin FeSe multilayer films, where we
find no electronic or structural change within the same temperature range. Our
experiments provide the first atomic-scale imaging of perturbation-driven
magnetic domain evolution simultaneous with the ensuing structural response of
the system. The results reveal surprising thermally-driven modulations of
antiferromagnetic domains in FeTe thin films well below the Neel temperature.
