Visualizing Heavy Fermions in Thin Films by in situ ARPES

Heavy Fermions are an important class of materials, which has attracted a lot of interest as they seemingly host a number of exotic ground states viz. unconventional superconductivity, Quantum Critical Fermi Liquid, FFLO states etc. Stabilizing these materials in a thin film form and extraction of their spectral function via ARPES opens up new possibilities of dimensional and strain tunability and in understanding and designing materials with exotic emergent properties. I will present our recent efforts in stabilizing thin films of Yb based heavy fermion compound YbAl$_{3}$ and the conventional metal analog LuAl$_{3}$ on MgO substrates. With the aid of an Al buffer layer crystalline, phase pure and fully-oriented epitaxial thin films can be grown with sub-nm surface roughness. Using \textit{insitu} angle resolved photoemission we, for the first time have been able to directly map out their electronic bandstructure and Fermi Surface. Measurements on LuAl$_{3}$ were found to be in good agreement with ab-initio calculations that provided us with an excellent reference to identify the signatures of heavy fermion formation in YbAl$_{3}$.