  High-throughput atomistic simulations reveal the unique effect of solute
atoms on twin variant selection in Mg-Al alloys. Twin embryos first undergo a
stochastic incubation stage when embryos choose which twin variant to adopt,
and then a deterministic growth stage when embryos expand without changing the
selected twin variant. An increase in Al composition promotes the stochastic
incubation behavior on the atomic level due to nucleation and pinning of
interfacial disconnections. At compositions above a critical value,
disconnection pinning results in multiple twin variant selection.
