STM Spectroscopic Mapping of Quasiparticle States in the Superconducting State of CeCoIn$_5$

The heavy fermion compounds provide an interesting playground to study strongly correlated physics, as a variety of unusual low-temperature states emerge in relatively close proximity to one another in their phase diagrams. However, to date, very little spectroscopic information about these low-temperature phases, including unconventional superconductivity, is known. Recently, at comparatively high temperatures, Aynajian and coworkers\footnote{P. Aynajian, {\it et al.}, {\it Nature} {\bf 486}, 201-206 (2012).} used scanning tunneling microscopy (STM) to visualize the formation of heavy quasiparticles in one of the prototype 115 compounds, CeCoIn$\mathrm{_5}$. Here, we use a new home-built STM to extend the spatial mapping of the electronic states of CeCoIn$_5$ down to its superconducting state at mK temperatures. This work was supported by the DOE and NSF.