Quantum Transport Theory with the Nonequilibrium Coherent Potentials

Abstract

Since any realistic electronic device has some degree of disorder, predicting disorder effects in quantum transport is a critical problem. Here we report the theory of nonequilibrium coherent potential approximation (NECPA) for analyzing disorder effects in nonequilibrium quantum transport of nanoelectronic devices. The NECPA is formulated by contour ordered nonequilibrium Green's function (NEGF) where the disorder average is carried out within the coherent potential approximation on the complex-time contour. We have derived a set of new rules that supplement the celebrated Langreth theorem and, as a whole, the generalized Langreth rules allow us to derive NECPA equations for real time Green's functions. The solution of NECPA equations provide the disorder averaged nonequilibrium density matrix as well as other relevant quantities for quantum transport calculations. We establish the excellent accuracy of NECPA by comparing its results to brute force numerical calculations of disordered tight-binding models. Moreover, the connection of NECPA equations which are derived on the complex-time contour, to the nonequilibrium vertex correction theory which is derived on the real-time axis, is made. As an application, we demonstrate that NECPA can be combined with density functional theory to enable analysis of nanoelectronic device physics from atomistic first principles.

16 pages, 6 figures

References in corpus (3)

• Electronic structures of III-V zinc-blende semiconductors from atomistic first principles
• Band offset of GaAs/AlxGa1-xAs heterojunctions from atomistic first principles
• Nonequilibrium Green's function theory for predicting device-to-device variability

Cited by in corpus (4)

• Generalized non-equilibrium vertex correction method in coherent medium theory for quantum transport simulation of disordered nanoelectronics
• Nonequilibrium DMFT+CPA for Correlated Disordered Systems
• Transport of Correlated Electrons through Disordered Chains: A Perspective on Entanglement, Conductance, and Disorder Averaging
• General method for calculating transport properties of disordered mesoscopic systems based on the nonequilibrium Green's function formalism