Calculation of the electronic structure and the magnetic properties of SrRuO3 and CaRuO3

We study the two pseudo-cubic perovskite ruthenates SrRuO3 and CaRuO3, by means of LSDA electronic structure calculations using the LMTO method for both the idealized cubic and the real orthorhombic structures. The LSDA calculations predict that both orthorhombic structures are ferromagnetic, with magnetic moments of 2.0 and 1.9 mu(B) respectively, while in the cubic structure, only SrRuO3 is magnetic (1.7 mu(B)). The general features of the DoS are in reasonable agreement with the experimental photoemission and EELS spectra However, the fine details of the DoS of these structures are sharply peaked near the position of epsilon(F) and this contributes to the high sensitivity of many of the calculated results as well as to strong variations of the properties of the real material. Magnetic moments and transport properties are examples of quantities exhibiting strong variations, but the calculations clearly show that the orthorhombic distortion is favourable for large spin splitting and low conductivity. A gap structure in the majority band just above epsilon(F) can be important for semi-metallic properties induced by distortions or charge transfers.