Superconducting Gap and Symmetry in FeSe1−xTex Studied by Specific Heat in Magnetic Fields

Takuya Konno, Tadashi Adachi, Masato Imaizumi, Takashi Noji, Takayuki Kawamata, Yoji Koike
2014 Journal of the Physical Society of Japan  
In order to investigate details of the superconducting (SC) gap in the iron-chalcogenide superconductors, the specific heat, C, of FeSe_1-x_Te_x_ with x=0.6-1 has been measured in magnetic fields. Using the two-gap model, it has been found that the smaller SC gap is significantly depressed by the application of magnetic field, resulting in the increase of the slope of the C/T vs T^2^ plot at low temperatures. From the specific-heat measurements at very low temperatures down to 0.4 K, it has
more » ... found that the enhancement of the residual electronic-specific-heat-coefficient in the ground state, gamma_0_, by the application of magnetic field is much smaller than that expected for superconductors with the typical s-wave or d-wave SC paring symmetry, which is in sharp contrast to the significant enhancement of gamma_0 observed in the iron-pnictide superconductors. These results are discussed in relation to the multi-band effect in the iron-based superconductors.
doi:10.7566/jpsj.83.094721 fatcat:oes75xvwb5c4fdmei6ib37p4xi