Dynamical simulations of radiation damage and defect mobility in MgO

被引:76
作者
Uberuaga, BP
Smith, R
Cleave, AR
Henkelman, G
Grimes, RW
Voter, AF
Sickafus, KE
机构
[1] Los Alamos Natl Lab, Los Alamos, NM 87545 USA
[2] Univ London Imperial Coll Sci Technol & Med, Dept Mat, London SW7 2BP, England
[3] Loughborough Univ Technol, Dept Math Sci, Loughborough LE11 3TU, Leics, England
来源
PHYSICAL REVIEW B | 2005年 / 71卷 / 10期
关键词
D O I
10.1103/PhysRevB.71.104102
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Collision cascades are investigated in MgO at energies ranging from 400 eV to 5 keV. Initial energy is imparted to the principle knock-on atom in the lattice and the cascade development is tracked using classical molecular dynamics. Temperature accelerated dynamics is performed on representative defects to follow the behavior to experimental time scales. Molecular statics is used to calculate basic properties of these defects, while density functional theory calculations are used to verify the potential. In the cascades performed at the lowest energy, the lattice either reforms perfectly or, if residual defects remain, these consist of isolated interstitials and vacancies and charge-neutral Mg-O divacancies and di-interstitials. As the energy is increased to 5 keV, isolated interstitials and di-interstitials remain the most common defects but more vacancy clustering can occur and interstitial defects consisting of up to seven atoms have been observed. Molecular statics calculations find that the binding energy per atom of the interstitial clusters increases from 3.5 to over 5 eV as the size increases from 2 to 16 atoms. Long-time-scale dynamics reveal that vacancies essentially never move at room temperature but that some interstitial clusters can diffuse quickly. Although tetrainterstitial interstitial clusters are essentially immobile, there is a long-lived metastable state of the hexainterstitial that diffuses one dimensionally on the nanosecond time scale at room temperature.
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页数:12
相关论文
共 40 条
[1]   MOLECULAR-DYNAMICS COMPUTER-SIMULATIONS OF DISPLACEMENT CASCADES IN METALS [J].
BACON, DJ ;
DELARUBIA, TD .
JOURNAL OF NUCLEAR MATERIALS, 1994, 216 :275-290
[2]   Computer simulation of displacement cascades and the defects they generate in metals [J].
Bacon, DJ ;
Gao, F ;
Osetsky, YN .
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 1999, 153 (1-4) :87-98
[3]  
Bader R. F. W., 1990, ATOMS MOL QUANTUM TH, V22
[4]   PROJECTOR AUGMENTED-WAVE METHOD [J].
BLOCHL, PE .
PHYSICAL REVIEW B, 1994, 50 (24) :17953-17979
[5]   Interstitial-oxygen-atom diffusion in MgO [J].
Brudevoll, T ;
Kotomin, EA ;
Christensen, NE .
PHYSICAL REVIEW B, 1996, 53 (12) :7731-7735
[7]   Predicted vacancy cluster structures in MgO and their interaction with helium [J].
Busker, G ;
van Huis, MA ;
Grimes, RW ;
van Veen, A .
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 2000, 171 (04) :528-536
[8]  
CATLOW CRA, 1982, COMPUTER SIMULATION
[9]   Oxygen interstitials in magnesium oxide: A band-model study [J].
Evarestov, RA ;
Jacobs, PWM ;
Leko, AV .
PHYSICAL REVIEW B, 1996, 54 (13) :8969-8972
[10]  
GRIMES R, UNPUB