  The structure of the Cu(110) surface is studied at high temperatures using a
combination of lattice-gas Monte Carlo and molecular dynamics methods with
identical many-atom interactions derived from the effective medium theory. The
anisotropic six-vertex model is used in the interpretation of the lattice-gas
results. We find a clear roughening transition around T_R=1000K and
T_R/T_M=0.81. Molecular dynamics reveals the clustering of surface defects as
the atomistic mechanism of the transition and allows us to estimate
characteristic time scales. For the system of size 50x50, the time scale of the
local roughening at 1150 K of an initially smooth surface is of the order of
100 ps.
