  Boson peak and beta-relaxation are two intrinsic and markedly different
dynamic modes of glasses, and their structural origins are long-standing
issues. Through tuning atomic packing of a model metallic glass with
microalloying of different types of elements, we find that low-temperature
boson heat capacity peak evolves hand in hand with high-temperature
beta-relaxation. A linear correlation between the boson peak temperature and
the activation energy of beta-relaxation is disclosed. The coupling of the
boson peak and the beta-relaxation indicates their common structural origin of
the loosely packed regions in metallic glasses.
