tomistix ToolKitList of Features

A

© QuantumWise A/S 2008–2013 Version: 13.8

ATK13.8

© QuantumWise A/S 2008–2013 Version: 13.8

Atomistix ToolKit (ATK) is a general-purpose atomic-scale modeling platform that combines a wide range of methods and models,

which can beused to study electronic structure and transport problems, or perform molecular dynamics calculations. ATK can compute

electrical, optical,mechanical and many other properties of nanostructures and materials. An easy-to-use graphical user interface makes

complex tasks simple to carry out, while a Python programming interface enables experienced users to efficiently implement complex

work-flows and perform advanced data analysis. ATK can also act as an interface to other codes, with capabilities to build geometries and

set up calculations for and read and plot output results produced by VASP, ABINIT, QuantumEspresso, etc. Users can furthermore extend

the capabilities and interfaces of the package by implementing their own plugins.

Atomic-scale computational methods● LCAO-based density functional theory (DFT)

» Numerical atomic orbital basis sets (SIESTA type)● Inclusion of indirect atom pairs for improved accuracy

» Norm-conserving (Troullier–Martins/HGH) pseudopotentials● IPotentials provided for LDA and GGA for almost all elements of the

periodic table, including semi-core potentials for many elements» Over 300 LDA/GGA exchange-correlation functionals via libXC

● IIncluding meta-GGA for accurate band gap calculations» van der Waals model (DFT-D2)» Noncollinear, restricted and unrestricted (spin-polarized) calculations

● IFor molecules, bulk, and devices» Hubbard U term in both LDA and GGA (also spin-dependent)

● I“Dual”, “on-site”, and “shell-wise” models» Counterpoise correction to counter basis set superposition errors (BSSE)» Ghost atoms (vacuum basis sets) for higher accuracy in the descriptionof surfaces and vacancies

● Plane-wave DFT» The ATK package includes a precompiled, parallel version of ABINIT, a leading plane-wave code» Control ABINIT from Python and set up calculations from the graphical user interface» See www.abinit.org for details on ABINIT features

● Semi-empirical tight binding» DFTB-type model, 30 different parameter sets are shipped with the product, and more can be downloaded and used directly» Interface for input of user-defined Slater-Koster parameters; built-in models for group IV and III-V semiconductors» Extended Hückel model with over 300 basis sets for (almost) every element in the periodic table» Spin polarization term can be added via internal database of spin-split parameters» All models adapted for self-consistent calculations

● IAdditional Hartree term for self-consistent response to the electrostatic environment● Classical potentials

» EMT, Brenner and Tersoff potentials● ISpecialized performance and stability features

» Initialization of a new calculation via the self-consistent density matrixof a converged one (with automatic spin alignment)

» Initialization of noncollinear spin calculations from collinear onesfor improved convergence

» Kerker preconditioner for improved convergence» Custom initial spin-filling schemes» Proprietary sparse matrix library for optimal performance

Transport calculations● Extended TranSIESTA-based method (self-energy coupling to semi-infinite leads)

for two-probe systems with open boundary conditions» Includes all spill-in contributions for density and matrix elements» Scattering states method for fast contour integration in non-equilibrium (finite bias)» Use of electronic free energy instead of total energy for open systems

● Non-equilibrium Green's function (NEGF) description of the electron distributionin the scattering region

● O(N) Greens function calculation and sparse matrix description of central region● Ability to treat systems with different electrodes – enables studies of single interfaces● Fast transmission spectrum calculation for perfectly periodic systems

Electrostatic model●Multi-grid or FFT solution to the Poisson equation

» Dirchlet, von Neumann or periodic boundary conditionscan be specified independently in each direction

» FFT2D Poisson solver for transport (multigrid in transport direction, FFT transversely)●Metallic gate electrodes and dielectric screening regions

» Allows for computation of transistor characteristics (gated structures)as well as charge stability diagrams of single-electron transistors

● Local atomic shifts to simulate external fields● Implicit solvent model● Charged systems with compensation charge to describe doping

Physical quantities (electronic structure)●Molecular spectra, also projected molecular spectra for periodic systems● Band structure (also projected) and effective mass analysis● Density of states (DOS), with projection onto atoms and angular momenta●Mulliken populations● Real-space 3D grid quantities

» Electron density» Effective potential» Electrostatic potential» Molecular orbitals» Bloch functions

● Forces (analytic Hellmann–Feynman)● Stress (analytic)● Electron localization function (ELF)● Polarization and piezoelectric tensor

Transport analysis● Ballistic coherent tunneling current and conductance● Transmission coefficients (k-point and energy resolved)● Transmission spectrum, eigenvalues, and eigenchannels● Device density of states, also projected on atoms and angular momenta● Voltage drop●Molecular projected self-consistent Hamiltonian (MPSH) eigenvalues● Complex band structure● Current density and transmission pathways● Real-space projected local density of states (LDOS)

Optical properties● Kubo-Greenwood formalism for linear optical properties● Calculation of optical adsorption, dielectric function, refractive index, etc

Ion dynamics● Computation of dynamical matrix

» Used for phonon properties like band structure, DOS, and thermal transport» Calculate the Seebeck coefficient and ZT by combining ionic and electronic results

● Quasi-Newton and FIRE methods for combined geometry and unit cell optimization( forces and stress )» Constraints: fixed atoms

● Geometry optimization under finite source–drain bias● Calculation of transition states, reaction pathways and energies using

nudged elastic bands (NEB) with climbing images» Pre-optimized path (improved Halgren–Lipscomb method)

●Molecular dynamics» Support for DFT, semi-empirical models, or classical potentials» NVE (Velocity Verlet), NPT/NVT (Berendsen/Melchionna)» Pre/post step hooks for custom on-the-fly analysis

Graphical user interface: Virtual NanoLab (VNL)● Atomic geometry builder for molecules, crystals, nanostructures and devices

» Coordinate tools: mirror, rotate, translate, free expression transform, etc» Bulk tools: symmetry information tool, supercells, etc» Surface cleaver and interface builder» NEB tools: set up path, edit images collectively or individually» Create device structures for transport calculations» Builders for nanostructures like graphene, nanotubes, nanowires» Crystal Builder» Import/export of many common atomic-scale modeling file formats

● Easy setup of calculations, even advanced work-flows

» Full range of functionality for ATK DFT, SemiEmpirical, Classical» Basic functionality of ABINIT

● Viewer for 3D data» Isosurfaces and contour plots» Control atom color, size, etc – also by data sets» Movies of MD or optimization trajectories» 3D scene control» Export images in most common graphical formats» Export CUBE or simple xy data files for external plotting

● Project management» Organize data files into projects» Easily transfer projects between computers, or share with other users» Overview all data in a project, or focus on particular subsets, then combine data sets from different files for advanced analysis

● Plugin API» Implement support for external codes

● IInput file generation (fully functional VASP scripter provided as example)● IRead data files for plotting and data analysis (CHGCAR, DOSCAR, etc)

» Add new features to the Builder● IAnything from simple operations to fully interactive widgets● IImport/export of structures in external file formats

» Add new data analysis capabilities and plot types● IColor atoms by data sets in the Viewer, integrate data, combine data into single plots, etc● IPython scripting language interface, directly coupled to GUI

» Can also be used interactively

Platform support● ATK is provided as a self-contained binary installer – no compilation needed

» GUI and backend version for 32- and 64-bit Windows and Linux●MPI parallelization on Windows and Linux

» Support for MPICH2 (Ethernet), MVAPICH2 (Infiniband), Intel MPI● OpenMP threading on multi-core processors● Floating license system (LM-X from X-Formation)

For more information, visit www.quantumwise.com

or contact info@quantumwise.com!

北京宏剑公司地址：北京市海淀区苏州街18号长远天地大厦A2座(四层)3A09室电话：010-51261900 传真：010-82610358 邮编：100080邮箱：sales@hongcam.com.cn 网址：www.hongcam.com.cn