scholarly journals KITE: high-performance accurate modelling of electronic structure and response functions of large molecules, disordered crystals and heterostructures

2020 ◽  
Vol 7 (2) ◽  
pp. 191809 ◽  
Author(s):  
Simão M. João ◽  
Miša Anđelković ◽  
Lucian Covaci ◽  
Tatiana G. Rappoport ◽  
João M. V. P. Lopes ◽  
...  
Keyword(s):  
Electronic Structure ◽  
High Performance ◽  
Large Scale ◽  
Green's Functions ◽  
Green’S Functions ◽  
Local Density ◽  
Tight Binding ◽  
Spectral Expansion ◽  
Real Space ◽  
Disordered Crystals

We present KITE, a general purpose open-source tight-binding software for accurate real-space simulations of electronic structure and quantum transport properties of large-scale molecular and condensed systems with tens of billions of atomic orbitals ( N ∼ 10 10 ). KITE’s core is written in C++, with a versatile Python-based interface, and is fully optimized for shared memory multi-node CPU architectures, thus scalable, efficient and fast. At the core of KITE is a seamless spectral expansion of lattice Green’s functions, which enables large-scale calculations of generic target functions with uniform convergence and fine control over energy resolution. Several functionalities are demonstrated, ranging from simulations of local density of states and photo-emission spectroscopy of disordered materials to large-scale computations of optical conductivity tensors and real-space wave-packet propagation in the presence of magneto-static fields and spin–orbit coupling. On-the-fly calculations of real-space Green’s functions are carried out with an efficient domain decomposition technique, allowing KITE to achieve nearly ideal linear scaling in its multi-threading performance. Crystalline defects and disorder, including vacancies, adsorbates and charged impurity centres, can be easily set up with KITE’s intuitive interface, paving the way to user-friendly large-scale quantum simulations of equilibrium and non-equilibrium properties of molecules, disordered crystals and heterostructures subject to a variety of perturbations and external conditions.

An Ab-Initio Multicenter Tight-Binding Model for Molecular Dynamics Simulations

1988 ◽  
Vol 141 ◽  
Author(s):  
Otto F. Sankey ◽  
David J. Niklewski
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Local Density ◽  
Tight Binding ◽  
Real Space ◽  
Hamiltonian Matrix ◽  
Binding Model ◽  
Annealing Study ◽  
Total Energies ◽  
Dynamics Simulations

AbstractA new, approximate method has been developed for computing total energies and forces for a variety of applications including molecular dynamics simulations of covalent materials. The method is tight-binding-like and is based on the local density approximation within the pseudopotential scheme. Slightly excited pseudo-atomic-orbitals are used, and the tight-binding Hamiltonian matrix is obtained in real space. The method is used to find the total energies for five crystalline phases of Si and the Si 2 molecule. Excellent agreement is found with experiment. A molecular dynamics simulated annealing study has been performed on the Si 3 molecule to determine the ground state configuration.

Electronic Structure Calculations on a Real-Space Mesh with Multigrid Acceleration

1995 ◽  
Vol 408 ◽  
Author(s):  
D. J. Sullivan ◽  
E. L. Briggs ◽  
C. J. Brabec ◽  
J. Bernholc
Keyword(s):  
Electronic Structure ◽  
Ab Initio ◽  
Large Scale ◽  
Electronic Structure Calculations ◽  
High Energy ◽  
Real Space ◽  
Parallel Architectures ◽  
Wurtzite Phase ◽  
Ongoing Work ◽  
Structure Calculations

AbstractWe have developed a set of techniques for performing large scale ab initio calculations using multigrid accelerations and a real-space grid as a basis. The multigrid methods permit efficient calculations on ill-conditioned systems with long length scales or high energy cutoffs. We discuss the design of pseudopotentials for real-space grids, and the computation of ionic forces. The technique has been applied to several systems, including an isolated C60 molecule, the wurtzite phase of GaN, a 64-atom cell of GaN with the Ga d-states in valence, and a 443-atom protein. The method has been implemented on both vector and parallel architectures. We also discuss ongoing work on O(N) implementations and solvated biomolecules.

Real-space multigrid-based approach to large-scale electronic structure calculations

1996 ◽  
Vol 54 (20) ◽  
pp. 14362-14375 ◽  
Author(s):  
E. L. Briggs ◽  
D. J. Sullivan ◽  
J. Bernholc
Keyword(s):  
Electronic Structure ◽  
Large Scale ◽  
Electronic Structure Calculations ◽  
Real Space ◽  
Structure Calculations

scholarly journals Thermal bridging of graphene nanosheets via covalent molecular junctions: A non-equilibrium Green’s functions–density functional tight-binding study

Nano Research ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 791-799 ◽  
Author(s):  
Diego Martinez Gutierrez ◽  
Alessandro Di Pierro ◽  
Alessandro Pecchia ◽  
Leonardo Medrano Sandonas ◽  
Rafael Gutierrez ◽  
...  
Keyword(s):  
Density Functional ◽  
Green's Functions ◽  
Green’S Functions ◽  
Graphene Nanosheets ◽  
Tight Binding ◽  
Molecular Junctions ◽  
Binding Study ◽  
Thermal Bridging ◽  
Non Equilibrium

Computation of impurity Green’s functions in the tight-binding scheme

1983 ◽  
Vol 2 (3) ◽  
pp. 721-730 ◽  
Author(s):  
F. del Giallo ◽  
P. Moretti ◽  
F. Pieralli
Keyword(s):  
Green's Functions ◽  
Green’S Functions ◽  
Tight Binding

Imaging the Nechako Basin, British Columbia, using ambient seismic noise1This article is one of a series of papers published in this Special Issue on the theme of New insights in Cordilleran Intermontane geoscience: reducing exploration risk in the mountain pine beetle-affected area, British Columbia.

2011 ◽  
Vol 48 (6) ◽  
pp. 1038-1049 ◽  
Author(s):  
O.A. Idowu ◽  
A.W. Frederiksen ◽  
J.F. Cassidy
Keyword(s):  
British Columbia ◽  
Surface Wave ◽  
Group Velocity ◽  
Large Scale ◽  
Green's Functions ◽  
Green’S Functions ◽  
Noise Analysis ◽  
Sedimentary Basins ◽  
Seismic Exploration ◽  
Velocity Models

The Nechako Basin in British Columbia, Canada is suspected to have hydrocarbon potential. However, it has been a difficult basin to explore because of the presence of Tertiary volcanic outcrop. The volcanic outcrop makes the use of conventional seismic exploration methods difficult owing to a strong velocity inversion at its base. An alternative is the passive source method known as ambient noise surface wave tomography. The method, which examines the high-frequency surface wave field that is obtained from noise analysis, is sensitive to large-scale crustal structure and has been successfully applied to measuring the depths of sedimentary basins. Station-to-station Green’s functions within the basin were estimated by cross-correlating the vertical components of the seismic noise data recorded by 12 POLARIS (Portable Observatories for Lithosphere Analysis and Research Investigating Seismicity) and CNSN (Canadian National Seismgraph Network) seismic stations between September 2006 and November 2007. The resulting Green’s functions were dominated by Rayleigh waves. The dispersion characteristics of the Rayleigh waveforms were measured within the microseismic band. Inversion of the dispersion curves produced 1-D and 2-D thickness models and 2-D group velocity models for the Nechako Basin and its surrounding region. The velocity models indicate two low group velocity structures within the basin that might represent sedimentary packages, and some pockets of high-velocity zones that show the presence of volcanic rocks within and on the basin. The thickness models indicated the presence of about six different velocity layers, in which the average thickness of the basin and the crust are ∼4.8 and 30–34 km, respectively.

Sign in / Sign up

Export Citation Format

Share Document