# Quantum transport simulation scheme including strong correlations and its application to organic radicals adsorbed on gold

## TL;DR

This paper introduces a computational scheme combining density functional theory, non-equilibrium Green's functions, and quantum Monte Carlo to accurately simulate quantum transport in nanoscale devices with strong correlations, exemplified by organic radicals on gold.

## Contribution

The authors develop a novel method integrating DFT, NEGF, and quantum Monte Carlo to model strong correlation effects in quantum transport, specifically applied to organic radicals on metal surfaces.

## Key findings

- Accurately predicts Kondo temperature and spectral functions.
- Achieves good agreement with experimental conductance measurements.
- Separates coherent and non-coherent transport contributions.

## Abstract

We present a computational method to quantitatively describe the linear-response conductance of nanoscale devices in the Kondo regime. This method relies on a projection scheme to extract an Anderson impurity model from the results of density functional theory and non-equilibrium Green's functions calculations. The Anderson impurity model is then solved by continuous time quantum Monte Carlo. The developed formalism allows us to separate the different contributions to the transport, including coherent or non-coherent transport channels, and also the quantum interference between impurity and background transmission. We apply the method to a scanning tunneling microscope setup for the 1,3,5-triphenyl-6-oxoverdazyl (TOV) stable radical molecule adsorbed on gold. The TOV molecule has one unpaired electron, which when brought in contact with metal electrodes behaves like a prototypical single Anderson impurity. We evaluate the Kondo temperature, the finite temperature spectral function and transport properties, finding good agreement with published experimental results.