Low Rank Approximation Method for Efficient Green's Function Calculation of Dissipative Quantum Transport

TL;DR

This paper introduces a low rank approximation technique for the NEGF method, significantly reducing computational resources and time in simulating quantum transport in nanodevices, with high accuracy demonstrated.

Contribution

The paper extends low rank approximation to NEGF, enabling efficient and accurate quantum transport simulations with substantial computational savings.

Findings

High agreement with exact NEGF results

Up to 150 times speed-up in computation

Reduced memory requirements

Abstract

In this work, the low rank approximation concept is extended to the non-equilibrium Green's function (NEGF) method to achieve a very efficient approximated algorithm for coherent and incoherent electron transport. This new method is applied to inelastic transport in various semiconductor nanodevices. Detailed benchmarks with exact NEGF solutions show 1) a very good agreement between approximated and exact NEGF results, 2) a significant reduction of the required memory, and 3) a large reduction of the computational time (a factor of speed up as high as 150 times is observed). A non-recursive solution of the inelastic NEGF transport equations of a 1000 nm long resistor on standard hardware illustrates nicely the capability of this new method.