1301.4487 (I K Dimitrov et al.)

Unusual persistence of superconductivity against high magnetic fields in
the strongly-correlated iron-chalcogenide film FeTe:O$_{x}$    [PDF]

I K Dimitrov, W D Si, W Ku, S J Han, J Jaroszynski

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.

View original: http://arxiv.org/abs/1301.4487