%0 Journal Article
%T Unusual persistence of superconductivity against high magnetic fields in the strongly-correlated iron-chalcogenide film FeTe:O$_{x}$
%A I. K. Dimitrov
%A W. D. Si
%A W. Ku
%A S. -J. Han
%A J. Jaroszynski
%J Physics
%D 2013
%I arXiv
%R 10.1063/1.4818790
%X We report an unusual persistence of superconductivity against high magnetic fields in the iron chalcogenide film FeTe:O$_{x}$ below ~ 2.5 K. Instead of saturating like a mean-field behavior with a single order parameter, the measured low-temperature upper critical field increases progressively, suggesting a large supply of superconducting states accessible via magnetic field or low-energy thermal fluctuations. We demonstrate that superconducting states of finite momenta can be realized within the conventional theory, despite its questionable applicability. Our findings reveal a fundamental characteristic of superconductivity and electronic structure in the strongly-correlated iron-based superconductors.
%U http://arxiv.org/abs/1301.4487v3