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The electronic and structural properties of pure and defective cerium oxide are investigated using a unified LDA+U approach which allows to treat the different valence states of Ce occurring for different stoichiometries on a same ground,…

Materials Science · Physics 2007-05-23 Stefano Fabris , Stefano de Gironcoli , Stefano Baroni

The previously proposed ansatz for density cumulant theory that combines orbital-optimization and a parameterization of the 2-electron reduced density matrix cumulant in terms of unitary coupled cluster amplitudes (OUDCT) is carefully…

Chemical Physics · Physics 2020-12-23 Jonathon P. Misiewicz , Justin M. Turney , Henry F. Schaefer , Alexander Yu. Sokolov

Machine-learning methods are nowadays of common use in the field of material science. For example, they can aid in optimizing the physicochemical properties of new materials, or help in the characterization of highly complex chemical…

Disordered Systems and Neural Networks · Physics 2022-11-29 Maciej J. Karcz , Luca Messina , Eiji Kawasaki , Serenah Rajaonson , Didier Bathellier , Emeric Bourasseau

To study crystals that contain heavy atoms, it is important to consider the relativistic effects, as electrons in orbitals close to the atom's nucleus can reach speeds comparable to that of light in a vacuum. In this study, we utilized the…

Materials Science · Physics 2024-04-25 Mahmoud Payami , Samira Sheykhi

Previous studies indicated that intrinsic point defects play a crucial role for the density of states of ferromagnetic half-metals in the band gap region: At large concentrations, defect-derived bands might close the gap at the Fermi energy…

Materials Science · Physics 2009-03-12 Björn Hülsen , Peter Kratzer , Matthias Scheffler

A cluster dynamics (CD) model has been developed to investigate the nucleation and growth of point defect clusters, i.e., interstitial prismatic loops and nanoscale and sub-nanoscale voids, in ThO2 during irradiation by energetic particles.…

Chemical nature of point defects, their segregation, cluster or complex formation in ZnO is an important area of investigation. In this report, 1.2 MeV Ar ion beam is used to incorporate defects in granular ZnO. Evolution of defective state…

Materials Science · Physics 2018-03-14 S. Pal , N. Gogurla , Avishek Das , S. S. Singha , P. Kumar , D. Kanjilal , A. Singha , S. Chattopadhyay , D. Jana , A. Sarkar

Stability of oxygen point defects in Ruddlesden-Popper oxides (La$_{1-x}$Sr$_{x}$)$_{2}$MO$_{4{\pm}{\delta}}$ (M = Co, Ni, Cu) is studied with density functional theory calculations to determine their stable sites, charge states, and…

Materials Science · Physics 2016-06-10 Wei Xie , Yueh-Lin Lee , Yang Shao-Horn , Dane Morgan

We present a study of the structural phase transition, mechanical and thermodynamic properties of UO$_{2}$ by means of the local density approximation (LDA)$+U$ approach. A phase transition pressure of 40 GPa, which agrees well with the…

Strongly Correlated Electrons · Physics 2013-09-25 Bao-Tian Wang , Ping Zhang , Raquel Lizárraga , Igor Di Marco , Olle Eriksson

The density functional theory (DFT) is used in a study of point defects on both UN (001) surface and sub-surface layers. We compare results for slabs of different thicknesses (both perfect and containing nitrogen or uranium vacancies) with…

Materials Science · Physics 2012-11-27 Dmitry Bocharov , Denis Gryaznov , Yuri F. Zhukovskii , Eugene A. Kotomin

We present a systematic analysis of molecular oxygen (O$_2$) adsorption trends on bimetallic PtNi clusters and their monometallic counterparts supported on MgO(100), by means of periodic DFT calculations for sizes between 25 up to 58 atoms.…

Materials Science · Physics 2016-04-12 Lauro Oliver Paz-Borbon , Francesca Baletto

We perform first-principles calculations of the quasiparticle defect states, charge transition levels, and formation energies of oxygen vacancies in rutile titanium dioxide. The calculations are done within the recently developed combined…

Materials Science · Physics 2014-07-23 Andrei Malashevich , Manish Jain , Steven G. Louie

We present predictions for the one-point probability distribution and cumulants of the transmitted QSO flux in the high redshift Lyman-$\alpha$ Forest. We make use of the correlation between the Lyman-$\alpha$ optical depth and the…

Astrophysics · Physics 2009-10-31 Enrique Gaztanaga , Rupert A. C. Croft

Relativistic $^{238}$U+$^{238}$U collisions have recently been used to extract the quadrupole shape of $^{238}$U. In this study, we employ state-of-the-art three-dimensional (3D) lattice covariant density functional theory (CDFT) with…

Nuclear Theory · Physics 2026-02-03 Yuan Li , Hao-jie Xu , Dandan Zhang , Guo-Liang Ma

Local density approximation (LDA) to the density functional theory (DFT) has continuous derivative of total energy as a number of electrons function and continuous exchange-correlation potential, while in exact DFT both should be…

Strongly Correlated Electrons · Physics 2010-06-28 V. I. Anisimov , A. V. Kozhevnikov , M. A. Korotin , A. V. Lukoyanov , D. A. Khafizullin

The nuclear-matter liquid-gas phase transition induces instabilities against finite-size density fluctuations. This has implications for both heavy-ion-collision and compact-star physics. In this paper, we study the clusterization…

Nuclear Theory · Physics 2008-11-26 C. Ducoin , J. Margueron , Ph. Chomaz

The stability and structures of Titanium-doped Gold clusters AunTi (n=2-16) are studied under the relativistic all-electron density-functional calculations. It is found that the most stable structures of AunTi clusters with n=2-7 are…

Atomic and Molecular Clusters · Physics 2007-05-23 Ming-Xing Chen , X. H. Yan

We propose a self-consistent site-dependent Hubbard $U$ approach for DFT+$U$ calculations of defects in complex transition-metal oxides, using Hubbard parameters computed via linear-response theory. The formation of a defect locally…

Materials Science · Physics 2019-04-04 Chiara Ricca , Iurii Timrov , Matteo Cococcioni , Nicola Marzari , Ulrich Aschauer

Uranium dioxide (UO$_2$) remains a formidable challenge for first-principles approaches, due to the complex interplay among spin-orbit coupling, Mott physics, magnetic ordering, and crystal distortions. Here we use DFT+$U$ to explore UO$_2$…

Ab initio perturbed ion plus polarization calculations are reported for doubly-charged nonstoichiometric (MgO)nMg2+ (n=1-29) cluster ions. We consider a large number of isomers with full relaxations of the geometries, and add the…

Atomic and Molecular Clusters · Physics 2009-10-31 Andres Aguado , Francisco Lopez-Gejo , Jose M. Lopez