  Topological aspects of surface states in semiconductors are studied by an
adiabatic deformation which connects a realistic system and a decoupled
covalent-bond model. Two topological invariants are focused. One is a quantized
Berry phase, and the other is a number of the edge states. A winding number as
another topological invariant is also considered. The surface states of Si and
Ge at (111), (110), and (100) surfaces are classified by the topological
invariants. Surface states of the GaAs as heterosemiconductors are also
discussed.
