ARPES

Material hosting quasiparticles acting as Weyl or Dirac fermions offer unique quantum phenomena which could be exploited in a completely new generation of electronic device. These materials are in general called topological semimetals, which differentiate from the topological insulator by hosting directly in the bulk band structure massless excitations, and not only at the surface. In this ongoing project we are characterizing different compounds with aim to discover new topological semimetals and explore the possible tunability of their topological phase by alloy engineering.

NavARP is an open source python project consisting on a companion application during Angle Resolved Photoemission Spectroscopy experiments, and a set of dedicated libraries for deep data analysis. The application has an interactive user interface for exploring the data, enriched by post-processing procedures (e.g. second derivative, Gaussian and Laplacian filters), giving access to the proper band structure axes (k-vectors, binding energy) after a guided transformation from the data acquisition ones (angles, kinetic energy). The so processed and transformed data can be then exported in different format for its inclusion in publications. The same, and more, functionalities are directly accessible in a python object-oriented library extending the possible data analysis work flow.

The extreme simplicity of its electronic structure has affirmed graphene as an ideal testbed for the demonstration of many-body effects on band structure. Within this context we have investigated: 1) the isotope substitution as an experimental tool to prove the electron-phonon coupling origin of sudden band slope change (known as kink) near the Fermi level; 2) highly doped graphene reaching almost the van-Hove singularity, to demonstrate that its apparent band flattening is just the unoccupied band spectral functional tails.