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 (I-n) with surprising properties; e.g., an I-4 is immobile, but an impinging I-2 can create a metastable I-6 that diffuses on the nanosecond time scale but is stable for years.
Uberuaga, B., Smith, R., Cleave, A., Montalenti, F., Henkelman, G., Grimes, R., et al. (2004). Structure and Mobility of Defects Formed from Collision Cascades in MgO. PHYSICAL REVIEW LETTERS, 92(11) [10.1103/PhysRevLett.92.115505].
Structure and Mobility of Defects Formed from Collision Cascades in MgO
MONTALENTI, FRANCESCO CIMBRO MATTIA;
2004
Abstract
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 (I-n) with surprising properties; e.g., an I-4 is immobile, but an impinging I-2 can create a metastable I-6 that diffuses on the nanosecond time scale but is stable for years.
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