Tuesday, April 16, 2013

1304.3785 (Shin-Ming Huang et al.)

Mechanism of High Temperature Superconductivity in Mesoscopically
Phase-Separated Ternary Iron Selenides

Shin-Ming Huang, Chung-Yu Mou, Ting-Kuo Lee
We examine superconductivity in the mesoscopically mixed antiferromagnetic (AF) and superconducting (SC) phases of ternary iron selenides K$_{y}$Fe$_{2-x}$Se$_{2}$. It is shown that the interlayer hopping and AF order are key factors to determine $T_c$ of SC phase. Contrary to the expected suppression of superconductivity due to competition between AF and SC phases in Fe-based materials, we find that larger AF orders actually results in larger SC orders, which explains the observed relatively high $T_c$ in these phases. On the other hand, the interlayer hopping generally results in deformed Fermi surfaces (FS's) that tend to suppress superconductivity. Our results indicate that by reducing the interlayer hopping appropriately, phase-separated K$_{y}$Fe$_{2-x}$Se$_{2}$ may exhibit the real SC phase with a much higher $T_c$ ($\sim 65K$) than what has been observed.
View original: http://arxiv.org/abs/1304.3785

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