Tight-binding implementation of the microcanonical approach to transport in nanoscale conductors: Generalization and analysis

Bushong, Sai, and Di Ventra (BSD) recently demonstrated that steady-state transport can emerge solely from quantum dynamics in a globally closed system consisting of a nanoscale conductor bridging two electrodes by Bushong et al. [Nano Lett. 5, 2569 (2005)]. They reported calculations, based on a simple tight-binding implementation of the “microcanonical” approach (TBIMCA) by Di Ventra and Todorov [J. Phys.: Condens. Matter 16, 8025 (2004)], in which a steady-state conductor current consistent in magnitude with the quantum conductance G0=2e2/h is established after an initial bias-induced imbalance in electrode populations begins to equalize. In this work, BSD’s TBIMCA is generalized, and their expressions for the time-dependent current and local occupation functions are shown to apply only to a restricted class of structures. Calculations of the current dynamics and local occupation functions, based on the generalized formalism, are then presented for a wide variety of electrode-conductor-electrode geomet...