Insight of volume-compression-induced changes in SrRuO3 from first-principles calculations

The changes in magnetic stabilization energy with volume for SrRuO3 are examined by means of the density functional theory calculations with on-site Coulomb interaction corrections to Ru 4d electrons. A robust magnetic ground state for SrRuO3 is found even when its volume is compressed to a value close to the experimental volume of the nonmagnetic (NM) CaRuO3. Nevertheless, the important ferromagnetic (FM) and half-metallic (HM) characters of SrRuO3 are found to destabilize during the process of volume compression. Corresponding to the change from FM to antiferromagnetic (AFM) character, the electrical property of the compound changes from conducting into insulating. The electronic structure calculations for SrRuO3 under various volume-compression cases show that the loss of HM is due to Ru 4dt2g states in minority band of SrRuO3 being pushed away from Fermi level. Further examination to the atomic positions before and after volume compression suggests the dramatic change of density of states at Fermi level may be due to the giant internal atomic displacements of Sr/O in SrRuO3.