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Electronic annealing Fermi Operator Expansion for DFT calculations on metallic systems

Electronic annealing Fermi Operator Expansion for DFT calculations on metallic systems
Electronic annealing Fermi Operator Expansion for DFT calculations on metallic systems
Density Functional Theory (DFT) calculations with computational effort which increases linearly with the number of atoms (linear-scaling DFT) have been successfully developed for insulators, taking advantage of the exponential decay of the one-particle density matrix. For metallic systems, the density matrix is also expected to decay exponentially at finite electronic temperature and linearscaling DFT methods should be possible by taking advantage of this decay. Here we present a method for DFT calculations at finite electronic temperature for metallic systems which is effectively linearscaling (O(N)). Our method generates the elements of the one-particle density matrix and also finds the required chemical potential and electronic entropy using polynomial expansions. A fixed expansion length is always employed to generate the density matrix, without any loss in accuracy by the application of a high electronic temperature followed by successive steps of temperature reduction until the desired (low) temperature density matrix is obtained. We have implemented this method in the ONETEP linear-scaling (for insulators) DFT code which employs local orbitals
that are optimised in situ. By making use of the sparse matrix machinery of ONETEP, our method exploits the sparsity of Hamiltonian and density matrices to perform calculations on metallic systems with computational cost that increases asymptotically linearly with the number of atoms. We demonstrate the linear-scaling computational cost of our method with calculation times on Palladium
nanoparticles with up to 13,000 atoms.
Density functional theory, Operator theory, Quantum ensemble theory, Nanoparticles, Entropy
0021-9606
Aarons, Jolyon
93e68133-73b0-43e0-8c91-464920f4a503
Skylaris, Chris-Kriton
8f593d13-3ace-4558-ba08-04e48211af61
Aarons, Jolyon
93e68133-73b0-43e0-8c91-464920f4a503
Skylaris, Chris-Kriton
8f593d13-3ace-4558-ba08-04e48211af61

Aarons, Jolyon and Skylaris, Chris-Kriton (2018) Electronic annealing Fermi Operator Expansion for DFT calculations on metallic systems. The Journal of Chemical Physics, 148 (7). (doi:10.1063/1.5001340).

Record type: Article

Abstract

Density Functional Theory (DFT) calculations with computational effort which increases linearly with the number of atoms (linear-scaling DFT) have been successfully developed for insulators, taking advantage of the exponential decay of the one-particle density matrix. For metallic systems, the density matrix is also expected to decay exponentially at finite electronic temperature and linearscaling DFT methods should be possible by taking advantage of this decay. Here we present a method for DFT calculations at finite electronic temperature for metallic systems which is effectively linearscaling (O(N)). Our method generates the elements of the one-particle density matrix and also finds the required chemical potential and electronic entropy using polynomial expansions. A fixed expansion length is always employed to generate the density matrix, without any loss in accuracy by the application of a high electronic temperature followed by successive steps of temperature reduction until the desired (low) temperature density matrix is obtained. We have implemented this method in the ONETEP linear-scaling (for insulators) DFT code which employs local orbitals
that are optimised in situ. By making use of the sparse matrix machinery of ONETEP, our method exploits the sparsity of Hamiltonian and density matrices to perform calculations on metallic systems with computational cost that increases asymptotically linearly with the number of atoms. We demonstrate the linear-scaling computational cost of our method with calculation times on Palladium
nanoparticles with up to 13,000 atoms.

Text pdf_archiveJCPSA6vol_148iss_7074107_1_am - Accepted Manuscript
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Accepted/In Press date: 29 January 2018
e-pub ahead of print date: 16 February 2018
Keywords: Density functional theory, Operator theory, Quantum ensemble theory, Nanoparticles, Entropy

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Local EPrints ID: 418440
URI: https://eprints.soton.ac.uk/id/eprint/418440
ISSN: 0021-9606
PURE UUID: fcb4f5fc-38e8-4dfd-b884-dc124dc8714c
ORCID for Chris-Kriton Skylaris: ORCID iD orcid.org/0000-0003-0258-3433

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Date deposited: 08 Mar 2018 17:30
Last modified: 17 Jul 2018 00:32

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Author: Jolyon Aarons

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