Structure and mobility of defects formed from collision cascades in MgO.
We study radiation-damage events in MgO on experimental time scales by augmenting molecular dynamics cascade simulations with temperature accelerated dynamics, molecular statics, and density functional theory. At 400 eV, vacancies and mono- and di-interstitials form, but often annihilate within milliseconds. At 2 and 5 keV, larger clusters can form and persist. While vacancies are immobile, interstitials aggregate into clusters (In) with surprising properties; e.g., an I4 is immobile, but an impinging I2 can create a metastable I6 that diffuses on the nanosecond time scale but is stable for years.
Uberuaga
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Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Smith
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Cleave
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Montalenti
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Henkelman
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Grimes
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Voter
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Sickafus
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