The Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ superconducting four-gap temperature evolution: a multi-band Chebyshev-BdG approach

David Moeckli; Evandro Vidor Lins de Mello

doi:10.1016/j.physleta.2016.05.054

paper

The Ba $_{0.6}$ K $_{0.4}$ Fe $_{2}$ As $_{2}$ superconducting four-gap temperature evolution: a multi-band Chebyshev-BdG approach

arXiv:1510.00167 · doi:10.1016/j.physleta.2016.05.054

Abstract

We generalize the Chebyshev-Bogoliubov-deGennes method to treat multi-band systems to address the temperature dependence of the superconducting (SC) gaps of iron based superconductors. Four SC gaps associated with different electron and hole pockets of optimally doped Ba $_{0.6}$ K $_{0.4}$ Fe $_{2}$ As $_{2}$ were clearly identified by angle resolved photo-emission spectroscopy. The few approaches that reproduces with success this gap structure are based on strong-coupling theories and required many adjustable parameters. We show that an approach with a redistribution of electron population between the hole and electron pockets $ν$ with evolving temperature reproduces the different coupling ratios $2 Δ^{ν} (0) / k_{B} T_{c}$ in these materials. We define the values that fit the four zero temperature gaps $Δ^{ν} (0)$ and after that all $Δ^{ν} (T)$ is obtained without any additional parameter.

5 pages, 2 figures

The Ba0.6​K0.4​Fe2​As2​ superconducting four-gap temperature evolution: a multi-band Chebyshev-BdG approach

Abstract

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The Ba $_{0.6}$ K $_{0.4}$ Fe $_{2}$ As $_{2}$ superconducting four-gap temperature evolution: a multi-band Chebyshev-BdG approach