Publications

Vanadium dioxide (VO\(_2\)) is a material that undergoes an insulator–metal transition upon heating above 340 K. It remains debated as to whether this electronic transition is driven by a corresponding structural transition or by strong electron–electron correlations. Here, we use apertureless scattering near-field optical microscopy to compare nanoscale images of the transition in VO\(_2\) thin films acquired at both mid-infrared and terahertz frequencies, using a home-built terahertz near-field microscope.

We consider the dimer Hubbard model within dynamical mean-field theory to study the interplay and competition between Mott and Peierls physics. We describe the various metal-insulator transition lines of the phase diagram and the breakdown of the different solutions that occur along them.

We study in detail the solution of a basic strongly correlated model,namely, the dimer Hubbard model. This model is the simplest realization of a cluster DMFT problem. We provide a detailed description of the solutions in the “coexistent region” where two (meta)stable states of the DMFT equations are found, one a metal and the other an insulator.

We consider a minimal model to investigate the metal-insulator transition in VO\(_2\). We adopt a Hubbard model with two orbitals per unit cell, which captures the competition between Mott and singlet-dimer localization. We solve the model within dynamical mean-field theory, characterizing in detail the metal-insulator transition and finding new features in the electronic states.