Improvements on non-equilibrium and transport Green function techniques: the next-generation transiesta

Abstract

We present novel methods implemented within the non-equilibrium Green function code (NEGF) transiesta based on density functional theory (DFT). Our flexible, next-generation DFT-NEGF code handles devices with one or multiple electrodes ($N_e\ge 1$) with individual chemical potentials and electronic temperatures. We describe its novel methods for electrostatic gating, contour opti- mizations, and assertion of charge conservation, as well as the newly implemented algorithms for optimized and scalable matrix inversion, performance-critical pivoting, and hybrid parallellization. Additionally, a generic NEGF post-processing code (tbtrans/phtrans) for electron and phonon transport is presented with several novelties such as Hamiltonian interpolations, $N_e\ge 1$ electrode capability, bond-currents, generalized interface for user-defined tight-binding transport, transmission projection using eigenstates of a projected Hamiltonian, and fast inversion algorithms for large-scale simulations easily exceeding $10^6$ atoms on workstation computers. The new features of both codes are demonstrated and bench-marked for relevant test systems.

24 pages, 19 figures

References in corpus (13)

• Heat Transport in low-dimensional systems
• Quantum thermal transport in nanostructures
• GOLLUM: a next-generation simulation tool for electron, thermal and spin transport
• Nonequilibrium Green's Function Approach to Phonon Transport in Defective Carbon Nanotubes
• Electrochemical doping of few layer ZrNCl from first-principles: electronic and structural properties in field-effect configuration
• Exact ground state density functional theory for impurity models coupled to external reservoirs and transport calculations
• DFT-based many-body analysis of electron transport through molecules
• First-principles scheme for spectral adjustment in nanoscale transport
• Ab initio study of charge transport through single oxygen molecules in atomic aluminum contacts
• Unravelling the role of inelastic tunneling into pristine and defected graphene
• Search for a Metallic Dangling-Bond Wire on $n$-doped H-passivated Semiconductor Surfaces
• Many-body current formula and current conservation for non-equilibrium fully interacting nanojunctions
• Enhancing the scalability and load balancing of the parallel selected inversion algorithm via tree-based asynchronous communication

Cited by in corpus (1)

• A tunable electronic beam splitter realized with crossed graphene nanoribbons