Linear response conductance of strongly interacting nanostructures using DMRG

Dan Bohr

Technical University of Denmark

Authors: Dan Bohr(1,2), Peter Schmitteckert(2), and Peter Wölfle(2) (1) MIC, Department of Micro and Nanotechnology, Technical University of Denmark, (2) TKM, Institut für Theorie der Kondensierten Materie, Universität Karlsruhe Abstract: In this work we present a novel approach for the calculation of transport properties of strongly correlated systems: a direct evaluation of the Kubo expression for the linear conductance by using the states and operators computed with the Density Matrix Renormalization Group (DMRG). Two different correlation functions are used to evaluate the conductance. The electrons are treated as one-dimensional spinless fermions, and the interactions are confined to a finite line segment which couples to two tight-binding leads. The developed method is benchmarked against the non-interacting limit, where the conductance can be calculated either by non-equilibrium Green¢s functions or by exact diagonalization. In the interacting case we present DMRG data for an extended nanostructure either in the Luttinger liquid regime or in the charge density wave regime. Finally we analyze the strongly interacting conductance using a simple model of hard-core particles on a reduced size lattice and emphasize the difference compared to an effective charging model.