Carbon-substitution dependent multiple superconducting gap ofMgB2: A sub-meV resolution photoemission study

S. Tsuda, T. Yokoya, T. Kiss, T. Shimojima, S. Shin, T. Togashi, S. Watanabe, C. Zhang, C. T. Chen, S. Lee, H. Uchiyama, S. Tajima (+2 others)
2005 Physical Review B  
"Sub-meV" resolution photoemission spectroscopy was used to study carbon-substitution dependence on the multiple superconducting gap of Mg(B$_{1 - x}$C$_{x})_{2}$. Two features corresponding to $\sigma $ and $\pi $ gaps are clearly observed in the raw spectra up to carbon concentration x = 7.5 {%}. The observed x dependence of the two gaps shows a qualitatively different behavior: a marked change of the $\sigma $ gap proportional to the $T_{c}$ variation and a negligible one of the $\pi $ gap.
more » ... of the $\pi $ gap. This as well as the temperature dependence can be explained with the two-band mean-field theory. Implications from the present study are discussed.
doi:10.1103/physrevb.72.064527 fatcat:j5s6gja3ovc5zhuyhjznampdbe