Efficient linear scaling method for computing the Landauer-Buttiker conductance

We report on a novel order N algorithm, that allows efficient computation of the Landauer-Buttiker conductance formula in heterojunctions of any complexity. The method is based on the recursive construction of a bi-orthogonal basis, in which non-hermitian hamiltonian matrices are first tridiagonalized, and continued-fraction expansion further used to accurately compute off-diagonal Green's function matrix elements. The method, of broad range of applicability, is here validated on tight-binding hamiltonians for nanotube-based intramolecular junctions.