  In the standard treatment of heterogeneous nucleation on a surface, the
energy of the surface is assumed to be homogeneous. Often its value is obtained
from some macroscopic measurement. We ask the question what happens if we
consider the surface energy to be heterogeneous. This is a straightforward
generalization and may realistically be important in a number of scenarios,
e.g. when the phase forming the surface is a binary alloy, solid solution, in
presence of self-organized or artifically created patterns on the surface. We
examine the effects of surface heterogeneity in a few scenarios in a model
system, 3D lattice Ising model. Utilizing umbrella sampling computer
simulations we find the nucleation barrier can be significantly lowered in
presence of surface heterogeneity, even if the average surface energy is kept
constant.
