Exploratory study of the electronic structure of fluorine-substituted Y${\mathrm{Ba}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_7$

The electronic structure of fluorine-substituted Y${\mathrm{Ba}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_7$ crystal is studied by means of first-principles calculations. Substitutions of O by one, two, and up to three F atoms on several selective O sites are studied. Implications of the present result on the possible mechanisms of high-$T_c$ superconductivity is discussed.