Irradiation of gallium arsenide (GaAs) produces immobile vacancies and mobile
interstitials. Tuttavia, after decades of experimental investigation, the
immobile Ga vacancy eludes observation, raising the question: Where is the Ga
vacancy? Static first-principles calculations predict a Ga vacancy should be
readily observed. We find that short-time dynamical evolution of primary
defects is key to explaining this conundrum. Introducing a multiscale
Atomistically Informed Device Engineering (AIDE) method, we discover that
during the initial displacement damage, the Fermi level shifts to mid-gap
producing oppositely charged vacancies and interstitials. Driven by Coulomb
attraction, fast As interstitials preferentially annihilate Ga vacancies,
causing their population to plummet below detectable limits before being
experimentally observed. This innovative model solves the mystery of the
missing Ga vacancy and reveals the importance of a multiscale approach to
explore the dynamical chemical behavior in experimentally inaccessible
short-time regimes.

Questo articolo esplora i giri e le loro implicazioni.

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