  We present an ab initio pseudopotential local density functional calculation
for stoichiometric high-Tc cuprate YBa_2Cu_3O_7 using the plane-wave basis set.
We have overcome well-known difficulties in applying pseudopotential methods to
first-row elements, transition metals, and rare-earth materials by carefully
generating norm-conserving pseudopotentials with excellent transferability and
employing an extremely efficient iterative diagonalization scheme optimized for
our purpose. The self-consistent band structures, the total and site-projected
densities of states, the partial charges and their symmetry-decompositions, and
some characteristic charge densities near E_f are presented. We compare our
results with various existing (F)LAPW and (F)LMTO calculations and establish
that the ab initio pseudopotential method is competitive with other methods in
studying the electronic structure of such complicated materials as high-Tc
cuprates. [8 postscript files in uuencoded compressed form]
