Cryogenic Scanning Tunneling Spectroscopy of Superconducting Iron Chalcogenide Single Crystals
ORAL
Abstract
We report scanning tunneling spectroscopy measurements on the iron-based superconductors of the ``11'' family including Fe$_{1-y}$Te$_{1-x}$Se$_{x}$ and Fe$_{1-y}$Te$_{1-x}$S$_{x}$. Conductance spectra and atomically-resolved images are obtained on single crystals down to 300 mK. A gap-like structure is observed, showing an asymmetric spectral background, non-trivial spatial variation and temperature dependence. We discuss our data in terms of possible gap anisotropy and doping inhomogeneities, and in relation to other recent spectroscopic measurements on iron-based superconductors.
*Work supported by NSERC, CFI/OIT, CIFAR, Taiwan National Science Council, U.S. DOE and Brookhaven Science Associates (No. DE-Ac02-98CH10886), and in part by the Center for Emergent Superconductivity, an Energy Frontier Research Center.
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