Tunneling STM/STS and break-junction spectroscopy of the layered nitro-chloride superconductors MNCl (M = Ti, Hf, Zr)

11th European Conference on Applied Superconductivity

Ekino, Toshikazu^1 ; Sugimoto, Akira^1 ; Gabovich, Alexander M.^2 ; Zheng, Zhanfeng^3 ; Zhang, Shuai^3 ; Yamanaka, Shoji^3

Hiroshima University, Graduate School of Integrated Arts and Sciences, Higashi-Hiroshima

739-8521, Japan^1

Institute of Physics, National Academy of Sciences, Nauka Ave. 46, Kyiv

03680, Ukraine^2

Hiroshima University, Graduate School of Engineering, Higashi-Hiroshima

7398527, Japan^3

关键词: Break junctions;    Critical temperatures;    Layered superconductor;    Nanometer length scale;    Scanning tunneling microscopy/spectroscopy;    Superconducting gaps;    Surface electronic structures;    Tunneling spectroscopy;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/507/1/012010/pdf
DOI  :  10.1088/1742-6596/507/1/012010

来源: IOP

【 摘 要 】

The layered superconductors β-MNCl with the critical temperatures Tc14 K (M Zr) - 25 K (M Hf) were investigated by means of scanning-tunneling microscopy/spectroscopy and break-junction tunneling spectroscopy. The STM/STS was used to investigate the surface electronic structures in nanometer length scale, while the BJTS was employed to precisely determine the gap characteristics. Both techniques consistently clarified the unusually large size of the superconducting gap. Wide gap distributions with large-scale maximum gap values were also revealed in α-KyTiNCl with a different crystal structure.