Dynamical vertex approximation for nanoscopic systems

TL;DR

This paper introduces a dynamical vertex approximation method for nanoscopic systems with strong correlations, demonstrating its effectiveness through modeling a quantum point contact and revealing a local Mott-Hubbard transition.

Contribution

It presents a new theoretical approach based on dynamical vertex approximation for modeling complex nanoscopic systems with strong electronic correlations.

Findings

The method reliably reproduces exact solutions at the one-particle level.

The quantum point contact becomes insulating before tunneling due to a local Mott-Hubbard transition.

The approach is validated on a system with 110 atoms.

Abstract

With an increasing complexity of nanoscopic systems and the modeling thereof, new theoretical tools are needed for a reliable calculation of complex systems with strong electronic correlations. To this end, we propose a new approach based on the recently introduced dynamical vertex approximation. We demonstrate its reliability already on the one-particle vertex (i.e., dynamical mean field theory) level by comparison with the exact solution. Modeling a quantum point contact with 110 atoms, we show that the contact becomes insulating already before entering the tunneling regime due to a local Mott-Hubbard transition occurring on the atoms which form the point contact.