Using scanning tunneling spectroscopy, we studied the transition from tunneling regime to local point contact on the iron-based superconductor Ba0.6K0.4Fe2As2. By gradually reducing the junction resistance, a series o...Using scanning tunneling spectroscopy, we studied the transition from tunneling regime to local point contact on the iron-based superconductor Ba0.6K0.4Fe2As2. By gradually reducing the junction resistance, a series of spectra were obtained with the characteristics evolving from single-particle tunneling into Andreev reflection. The spectra can be well fitted to the modified Blonder–Tinkham–Klapwijk（BTK） model and exhibit significant changes of both spectral broadening and orbital selection due to the formation of point contact. The spatial resolution of the point contact was estimated to be several nanometers, providing a unique way to study the inhomogeneity of unconventional superconductors on such a scale.展开更多
We report scanning tunneling microscopy/spectroscopy（STM/STS） studies on iron-based superconductors of Ba1-xKxFe2As2 and nearly optimally doped Fe（Te,Se）. Mode-like features were observed universally outside the s...We report scanning tunneling microscopy/spectroscopy（STM/STS） studies on iron-based superconductors of Ba1-xKxFe2As2 and nearly optimally doped Fe（Te,Se）. Mode-like features were observed universally outside the superconducting gaps in the tunneling spectra, which are similar to our previous observations in other samples and can be ascribed to the interaction between electrons and spin excitations. Furthermore, an almost linear relationship between the superconducting gaps and the superconducting transition temperatures was noted and should also be taken into account in understanding the mechanism of iron-based superconductors.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11574372 and 11322432)the“Strategic Priority Research Program(B)”of the Chinese Academy of Sciences(Grant No.XDB07020300)
文摘Using scanning tunneling spectroscopy, we studied the transition from tunneling regime to local point contact on the iron-based superconductor Ba0.6K0.4Fe2As2. By gradually reducing the junction resistance, a series of spectra were obtained with the characteristics evolving from single-particle tunneling into Andreev reflection. The spectra can be well fitted to the modified Blonder–Tinkham–Klapwijk（BTK） model and exhibit significant changes of both spectral broadening and orbital selection due to the formation of point contact. The spatial resolution of the point contact was estimated to be several nanometers, providing a unique way to study the inhomogeneity of unconventional superconductors on such a scale.
基金supported by the National Basic Research Program of China(Grant Nos.2011CBA00110 and 2012CB821403)the National Natural Science Foundation of China(Grant Nos.11174349 and 11322432)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB07020300)
文摘We report scanning tunneling microscopy/spectroscopy（STM/STS） studies on iron-based superconductors of Ba1-xKxFe2As2 and nearly optimally doped Fe（Te,Se）. Mode-like features were observed universally outside the superconducting gaps in the tunneling spectra, which are similar to our previous observations in other samples and can be ascribed to the interaction between electrons and spin excitations. Furthermore, an almost linear relationship between the superconducting gaps and the superconducting transition temperatures was noted and should also be taken into account in understanding the mechanism of iron-based superconductors.
