paper

Probing superconducting energy gap from infrared spectroscopy on a Ba $_{0.6}$ K $_{0.4}$ Fe $_{2}$ As $_{2}$ single crystal with T $_{c}$ =37 K

arXiv:0807.1094 · doi:10.1103/PhysRevLett.101.107004

Abstract

We performed optical spectroscopy measurement on a superconducting Ba $_{0.6}$ K $_{0.4}$ Fe $_{2}$ As $_{2}$ single crystal with T $_{c}$ =37 K. Formation of the superconducting energy gaps in the far-infared reflectance spectra below T $_{c}$ is clearly observed. The gap amplitudes match well with the two distinct superconducting gaps observed in angle-resolved photoemission spectroscopy experiments on different Fermi surfaces. We determined absolute value of the penetration depth at 10 K as $I^» ≃ 2000 A ~$ . A spectral weight analysis shows that the Ferrell-Glover-Timkham sum rule is satisfied at low energy scale, less than 6 $I^$ .

4 pages, 5 figures

Probing superconducting energy gap from infrared spectroscopy on a Ba0.6​K0.4​Fe2​As2​ single crystal with Tc​=37 K

Abstract

Probing superconducting energy gap from infrared spectroscopy on a Ba $_{0.6}$ K $_{0.4}$ Fe $_{2}$ As $_{2}$ single crystal with T $_{c}$ =37 K