  We study the dynamics of bound pairs in the extended Hubbard model driven by
a linear external field. It is shown that two interacting bosons or singlet
fermions with nonzero on-site and nearest-neighbor interaction strengths can
always form bound pairs in the absence of an external field. There are two
bands of bound pairs, one of which may have incomplete wave vectors when it has
an overlap with the scattering band, referred to as an imperfect band. In the
presence of the external field, the dynamics of the bound pair in the perfect
band exhibits distinct Bloch-Zener oscillation (BZO), while in the imperfect
band the oscillation presents a sudden death. The pair becomes uncorrelated
after the sudden death and the BZO never comes back. Such dynamical behaviors
are robust even for the weak-coupling regime and thus can be used to
characterize the phase diagram of the bound states.
