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

摘要

We present a computational method to quantitatively describe thelinear-response conductance of nanoscale devices in the Kondo regime. Thismethod relies on a projection scheme to extract an Anderson impurity model fromthe results of density functional theory and non-equilibrium Green's functionscalculations. The Anderson impurity model is then solved by continuous timequantum Monte Carlo. The developed formalism allows us to separate thedifferent contributions to the transport, including coherent or non-coherenttransport channels, and also the quantum interference between impurity andbackground transmission. We apply the method to a scanning tunneling microscopesetup for the 1,3,5-triphenyl-6-oxoverdazyl (TOV) stable radical moleculeadsorbed on gold. The TOV molecule has one unpaired electron, which whenbrought in contact with metal electrodes behaves like a prototypical singleAnderson impurity. We evaluate the Kondo temperature, the finite temperaturespectral function and transport properties, finding good agreement withpublished experimental results.