Chapter 7 Nonequilibrium Green's function modeling of the quantum transport of molecular electronic devices

Abstract

Publisher Summary This chapter discusses the nonequilibrium Green's function (NEGF) modeling of the quantum transport of molecular electronic devices. All the theoretical approaches to the accurate modeling of quantum transport of molecular devices fall into four main categories: semi-empirical methods, supercell methods, the open-jellium Lippman-Schwinger approach, and the NEGF approach. The key feature of the NEGF formalism is that the self-consistent charge density is not constructed out of the eigenstates of the system. Rather, the charge density is determined via the Keldysh NEGFs that provide an efficient framework for dealing with an open quantum system. The NEGF–DFT formalism for quantum transport provides important contributions toward calculating the device properties of real materials systems, especially when combined with the power of parallel supercomputers. The incorporation of spin-dependent effects opens up the important field of nanoscale magnetoelectronics or “spintronics.” In magnetoelectronics, both the charge and the spin degrees of freedom are utilized for the operation of a functional device.