Observation of mode-like features in tunneling spectra of iron-based superconductors<xref ref-type="fn" rid="cpb151073fn1">*</xref>

Observation of mode-like features in tunneling spectra of iron-based superconductors*

Gong Jing^a), Hou Xing-Yuan^a), Zhu Jun^a), Jie Yun-Yin^a), Gu Ya-Dong^a),^b), Shen Bing^a), Ren Cong^a), Li Chun-Hong^a), Shan Lei†^a),^c)

Atomic topography and tunneling spectra of Fe(Te,Se) single crystal. (a) Schematic crystal structure of a single Fe(Te,Se) block. (b) Topographic image of Fe(Te, Se) (17 nm×17 nm). The exposed surface is the Se/Te layer, wherein the bright dots are Te atoms and the less bright dots are Se atoms. It was taken at 2.4 K with a bias voltage of 20 mV and a tunneling current of 250 pA. (c) Tunneling spectra taken on the surface of Fe(Te, Se) at different temperatures. (d) The spectra in panel (c) normalized to the spectrum taken at 10.1 K. All the spectra in panels (c) and (d) are shifted for clarity. Dotted lines indicate the location where the bosonic mode lies.