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
TLDR
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.Abstract:
We have developed and implemented 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. Exchange and correlation are treated with the local spin density or generalized gradient approximations. The basis functions and the electron density are projected on a real-space grid, in order to calculate the Hartree and exchange-correlation potentials and matrix elements, with a number of operations that scales linearly with the size of the system. We use a modified energy functional, whose minimization produces orthogonal wavefunctions and the same energy and density as the Kohn-Sham energy functional, without the need for an explicit orthogonalization. Additionally, using localized Wannier-like electron wavefunctions allows the computation time and memory required to minimize the energy to also scale linearly with the size of the system. Forces and stresses are also calculated efficiently and accurately, thus allowing structural relaxation and molecular dynamics simulations.read more
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Impurity-ion pair induced high-temperature ferromagnetism in Co-doped ZnO
TL;DR: In this article, it was shown that magnetism originates from oxygen-vacancy pairs with a partially filled level close to the ZnO conduction-band minimum, and that the magnetic interaction between these pairs is sufficiently long ranged to cause percolation at moderate concentrations.
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Electron and hole dynamics in dye-sensitized solar cells: influencing factors and systematic trends.
TL;DR: Understanding of these effects at the atomic level suggests tunable parameters through which the electronic characteristics of dye-sensitized solar cell devices can be improved and their efficiency can be maximized.
Journal ArticleDOI
Ultrathin Zirconium Disulfide Nanodiscs
Jung Tak Jang,Sohee Jeong,Jung Wook Seo,Min-Cheol Kim,Eunji Sim,Yuhong Oh,Seunghoon Nam,Byungwoo Park,Jinwoo Cheon +8 more
TL;DR: The nanoscale thickness and lateral size of UT-ZrS(2) discs are critical for fast and reliable intercalation cycling because those dimensions both increase the surface area and provide open edges that enhance the diffusion kinetics for guest molecules.
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Formation of nitrogen-doped graphene nanoscrolls by adsorption of magnetic γ-Fe2O3 nanoparticles.
Tiva Sharifi,Eduardo Gracia-Espino,Hamid Reza Barzegar,Xueen Jia,Florian Nitze,Guangzhi Hu,Per Nordblad,Cheuk-Wai Tai,Thomas Wågberg +8 more
TL;DR: This work reports a 100% efficient process to transform nitrogen-doped reduced graphene oxide sheets into homogeneous nanoscrolls by decoration with magnetic γ-Fe2O3 nanoparticles, and concludes that the rolling is initiated by the strong adsorption of maghemite nanoparticles at nitrogen defects in the graphene lattice.
Journal ArticleDOI
Electronic transport between graphene layers covalently connected by carbon nanotubes.
TL;DR: A first-principles study of the electronic transport properties of metallic and semiconducting carbon nanotube (CNT) junctions connecting two graphene layers, for different CNT lengths and link structures finds that, for metallic CNTs, the conductance is nearly independent of the tube length, but changes strongly with the link structure.
References
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Generalized Gradient Approximation Made Simple
TL;DR: A simple derivation of a simple GGA is presented, in which all parameters (other than those in LSD) are fundamental constants, and only general features of the detailed construction underlying the Perdew-Wang 1991 (PW91) GGA are invoked.
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Special points for brillouin-zone integrations
Hendrik J. Monkhorst,J.D. Pack +1 more
TL;DR: In this article, a method for generating sets of special points in the Brillouin zone which provides an efficient means of integrating periodic functions of the wave vector is given, where the integration can be over the entire zone or over specified portions thereof.
Journal ArticleDOI
Self-Consistent Equations Including Exchange and Correlation Effects
Walter Kohn,L. J. Sham +1 more
TL;DR: In this paper, the Hartree and Hartree-Fock equations are applied to a uniform electron gas, where the exchange and correlation portions of the chemical potential of the gas are used as additional effective potentials.
Book
Introduction to solid state physics
TL;DR: In this paper, the Hartree-Fock Approximation of many-body techniques and the Electron Gas Polarons and Electron-phonon Interaction are discussed.