Self-consistent order- N density-functional calculations for very large systems
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A method to perform fully self-consistent density-functional calculations that scales linearly with the system size and which is well suited for very large systems is presented, using strictly localized pseudoatomic orbitals as basis functions.Abstract:
We present a method to perform fully self-consistent density-functional calculations that scales linearly with the system size and which is well suited for very large systems. It uses strictly localized pseudoatomic orbitals as basis functions. The sparse Hamiltonian and overlap matrices are calculated with an $O(N)$ effort. The long-range self-consistent potential and its matrix elements are computed in a real-space grid. The other matrix elements are directly calculated and tabulated as a function of the interatomic distances. The computation of the total energy and atomic forces is also done in $O(N)$ operations using truncated, Wannier-like localized functions to describe the occupied states, and a band-energy functional which is iteratively minimized with no orthogonality constraints. We illustrate the method with several examples, including carbon and silicon supercells with up to 1000 Si atoms and supercells of $\ensuremath{\beta}$-${\mathrm{C}}_{3}$${\mathrm{N}}_{4}$. We apply the method to solve the existing controversy about the faceting of large icosahedral fullerenes by performing dynamical simulations on ${\mathrm{C}}_{60}$, ${\mathrm{C}}_{240}$, and ${\mathrm{C}}_{540}$.read more
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Journal ArticleDOI
The SIESTA method for ab initio order-N materials simulation
José M. Soler,Emilio Artacho,Julian D. Gale,Alberto García,Javier Junquera,Javier Junquera,Pablo Ordejón,Daniel Sánchez-Portal +7 more
TL;DR: In this paper, a selfconsistent density functional method using standard norm-conserving pseudopotentials and a flexible, numerical linear combination of atomic orbitals basis set, which includes multiple-zeta and polarization orbitals, was developed and implemented.
Journal ArticleDOI
QUICKSTEP: Fast and accurate density functional calculations using a mixed Gaussian and plane waves approach
Joost VandeVondele,Matthias Krack,Fawzi Mohamed,Michele Parrinello,Thomas Chassaing,Jürg Hutter +5 more
TL;DR: It is shown how derivatives of the GPW energy functional, namely ionic forces and the Kohn–Sham matrix, can be computed in a consistent way and the computational cost is scaling linearly with the system size, even for condensed phase systems of just a few tens of atoms.
Book
Electronic Structure: Basic Theory and Practical Methods
TL;DR: In this paper, the Kohn-Sham ansatz is used to solve the problem of determining the electronic structure of atoms, and the three basic methods for determining electronic structure are presented.
Journal ArticleDOI
Density-functional method for very large systems with LCAO basis sets
TL;DR: In this article, a linear scaling, fully self-consistent density-functional method for performing first-principles calculations on systems with a large number of atoms, using standard norm-conserving pseudopotentials and flexible linear combinations of atomic orbitals (LCAO) basis sets, was implemented.
Journal ArticleDOI
Hybrid passivated colloidal quantum dot solids
Alexander H. Ip,Susanna M. Thon,Sjoerd Hoogland,Oleksandr Voznyy,David Zhitomirsky,Ratan Debnath,Larissa Levina,Lisa R. Rollny,Graham H. Carey,Armin Fischer,Kyle W. Kemp,Illan J. Kramer,Zhijun Ning,André J. Labelle,Kang Wei Chou,Aram Amassian,Edward H. Sargent +16 more
TL;DR: The density of midgap trap states in CQD solids is quantified and shown to be limited by electron-hole recombination due to these states, and a robust hybrid passivation scheme is developed that can passivate trap sites that are inaccessible to much larger organic ligands.
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