  The spin Hall conductivity is usually calculated for periodic solids, while
the knowledge of local contributions from inhomogeneous regions like interfaces
or surfaces would be desirable. In this work we derive a local expression for
the spin Hall conductivity of two-dimensional systems in analogy to the local
anomalous Hall conductivity discussed recently. Our approach is applicable to
heterogeneous fully bounded systems and nanoribbons with both open and periodic
boundary conditions.
