Electronic structure of Ca2RuO4: A comparison with the electronic structures of other ruthenates

Density-functional calculations are used to study the electronic and magnet ic structures of Ca2RuO4. It is found that the magnetic and structural degr ees of freedom are strongly coupled. It is also found that the electronic s tructure near the Fermi level is described by the antibonding Ru 4d and O 2 p bands as is the case for other 4d Ruddlesden-Popper materials. The distor tion of the lattice has a pronounced effect on the magnetic ordering and lo calization of the carriers. The calculations give a good estimate of the ma gnetic moment and they indicate that there is a magnetic instability in thi s compound.