Infrared probe of the gap evolution across the phase diagram of Ba$_{1-x}$K$_{x}$Fe$_{2}$As$_{2}$

B. Xu; Y. M. Dai; H. Xiao; B. Shen; H. H. Wen; X. G. Qiu; R. P. S. M. Lobo

doi:10.1103/PhysRevB.96.115125

paper

Infrared probe of the gap evolution across the phase diagram of Ba $_{1 - x}$ K $_{x}$ Fe $_{2}$ As $_{2}$

arXiv:1709.05485 · doi:10.1103/PhysRevB.96.115125

Abstract

We measured the optical conductivity of superconducting single crystals of Ba $_{1 - x}$ K $_{x}$ Fe $_{2}$ As $_{2}$ with $x$ ranging from 0.40 (optimal doping, $T_{c} = 39$ K) down to 0.20 (underdoped, $T_{c} = 16$ K), where a magnetic order coexists with superconductivity. In the normal state, the low-frequency optical conductivity can be described by an incoherent broad Drude component and a coherent narrow Drude component: the broad one is doping-independent, while the narrow one shows strong scattering in the heavily underdoped compound. In the superconducting state, the formation of the condensate leads to a low-frequency suppression of the optical conductivity spectral weight. In the heavily underdoped region, the superfluid density is significantly suppressed, and the weight of unpaired carriers rapidly increases. We attribute these results to changes in the superconducting gap across the phase diagram, which could show a nodal-to-nodeless transition due to the strong interplay between magnetism and superconductivity in underdoped Ba $_{1 - x}$ K $_{x}$ Fe $_{2}$ As $_{2}$ .

Infrared probe of the gap evolution across the phase diagram of Ba $_{1 - x}$ K $_{x}$ Fe $_{2}$ As $_{2}$

Abstract

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Infrared probe of the gap evolution across the phase diagram of Ba1−x​Kx​Fe2​As2​

Abstract

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Cited by in corpus (5)

Infrared probe of the gap evolution across the phase diagram of Ba $_{1 - x}$ K $_{x}$ Fe $_{2}$ As $_{2}$