  We present the electronic band structure of the interfaces
$YBa_2Cu_3O_7/GaAs$ (direct gap) and $YBa_2Cu_3O_7/AlAs$ (indirect gap) in
different configurations calculated using the Density Functional Theory as in
the Wien2k code within the local density approximation. We have projected the
density of states at the atomic layers forming the interface. We concentrated
in the semiconductor side. The two first atomic layers in the semiconductor
side of the interface present a clear metallic behavior. We found for both
semiconductors considered that it converges towards the bulk atomic-layer
projected density of states at the fifth atomic layer from the interface. We
considered an ideal non-reconstructed interface in the (001) direction in this
work. This behavior is interesting and could be used in several technological
applications.
