Real space imaging and temperature tunability of magnetic domain walls in FeTe thin films.

External parameters such as strain and temperature can have pronounced effects on the electronic properties of solids. Here we synthesize thin films of the parent non-superconducting compound of FeTe using molecular beam epitaxy (MBE). We use spin-polarized scanning-tunneling microscopy (SP-STM) to map the local antiferromagnetic (AFM) order as a function of temperature. We observe nanoscale magnetic domains, which shift irreversibly with a rise in temperature. These simultaneously correlate to the local anisotropic strain along the Te-Te direction. Our studies suggest that temperature changes can dramatically change the microscopic profile of AFM domains. We conclude by discussing the implications of our results on the domain wall formation in FeTe.