  We present an embedding scheme for periodic systems that facilitates the
treatment of the physically important part (here the unit cell) with advanced
electronic-structure methods, that are computationally too expensive for
periodic systems. The rest of the periodic system is treated with
computationally less demanding approaches, e.g., Kohn-Sham density-functional
theory, in a self- consistent manner. Our scheme is based on the concept of
dynamical mean-field theory (DMFT) formulated in terms of Green functions. In
contrast to the original DMFT formulation for correlated model Hamiltonians, we
here consider the unit cell as local embedded cluster in a first-principles
way, that includes all electronic degrees of freedom. Our real-space dynamical
mean-field embedding (RDMFE) scheme features two nested Dyson equations, one
for the embedded cluster and another for the periodic surrounding. The total
energy is computed from the resulting Green functions. The performance of our
scheme is demonstrated by treating the embedded region with hybrid functionals
and many-body perturbation theory in the GW approach for simple bulk systems.
The total energy and the density of states converge rapidly with respect to the
computational parameters and approach their bulk limit with increasing cluster
(i.e., unit cell) size.
