First Principles Quantum Transport with Electron-vibration Interactions: A Maximally Localized Wannier Function Approach

摘要

We present an ab initio inelastic quantum transport approach based onmaximally localized Wannier functions. Electronic-structure properties arecalculated with density-functional theory in a planewave basis, andelectron-vibration coupling strengths and vibrational properties are determinedwith density-functional perturbation theory. Vibration-induced inelastictransport properties are calculated with non-equilibrium Green's functiontechniques, which are based on localized orbitals. For this purpose weconstruct maximally localized Wannier functions. Our formalism is applied toinvestigate inelastic transport in a benzene molecular junction connected tomono-atomic carbon chains. In this benchmark system the electron-vibrationself-energy is calculated either in the self-consistent Born approximation orby lowest-order perturbation theory. It is observed that upward and downwardconductance steps occur, which can be understood using multi-eigenchannelscattering theory and symmetry conditions. In a second example where themono-atomic carbon chain electrode is replaced by a (3; 3) carbon nanotube, wefocus on the non-equilibrium vibration populations driven by the conductingelectrons using a semi-classical rate equation.