Observation of multiple superconducting gaps in Fe1+yTe1-xSex via a   nano-scale approach to point-contact spectroscopy
  We report a distinct experimental approach to point-contact Andreev reflection spectroscopy with diagnostic capability via a unique design of nano-scale normal metal/superconductor devices with excellent thermo-mechanical stability, and have employed this method to unveil the existence of two superconducting energy gaps in iron chalcogenide Fe1+yTe1-xSex which is crucial for understanding its pairing mechanism. This work opens up new opportunities to study gap structures in superconductors and elemental excitations in solids. 
Haibing Peng, Debtanu De, Zheng Wu, Carlos Diaz-Pinto
cond-mat.supr-con cond-mat.str-el