Observation of mode-like features in tunneling spectra of iron-based superconductors*
Gong Jinga), Hou Xing-Yuana), Zhu Juna), Jie Yun-Yina), Gu Ya-Donga),b), Shen Binga), Ren Conga), Li Chun-Honga), Shan Lei†a),c)
       
(a) The averaged d I /d V spectra (over a 10 nm×10 nm region) of Ba1− x K x Fe2As2 with T c = 22 K. (b) The averaged d I /d V spectra (over a 8.3 nm×8.3 nm region) of Ba1− x K x Fe2As2 with T c = 16 K. Panels (c) and (d) present the derivatives of the 2.2 K spectra shown in panels (a) and (b), respectively.