  We theoretically investigate high-pressure effects on the atomic dynamics of
metallic glasses. The theory predicts compression-induced rejuvenation and the
resulting strain hardening that have been recently observed in metallic
glasses. Structural relaxation under pressure is mainly governed by local cage
dynamics. The external pressure restricts the dynamical constraints and slows
down the atomic mobility. In addition, the compression induces a rejuvenated
metastable state (local minimum) at a higher energy in the free energy
landscape. Thus, compressed metallic glasses can rejuvenate and the
corresponding relaxation is reversible. This behavior leads to strain hardening
in mechanical deformation experiments. Theoretical predictions agree well with
experiments.
