ARPES study of FeTe single crystal and FeTeO$_{x}$ films*

We have performed an ARPES investigation of FeTe single crystals, films, as well as the novel superconducting film FeTeOx. Our results from the single crystals reflect the previously reported Fermi surface pocket around the X-point [($\pi $,0)], possibly connected to a spin-density wave (SDW) order [Y. Xia, PRL 103, 037002 (2009)] . Unlike this previous report, our results also reveal the presence of an energy gap which would be expected from the SDW order. The temperature dependence shows that the gap closes in the rough vicinity of the magnetic transition temperature, supporting it's interpretation as reflecting the SDW state. We were able to produce an ARPES quality surface by cleaving films of FeTe and FeTeO$_{x}$, with the FeTe films showing similar features as the bulk.