Unrestricted Hartree-Fock Analysis of Sr3-xCaxRu2O7
Abstract
We investigated the electronic and magnetic structure of Sr3-xCaxRu2O7 (0 ≤ x ≤ 3) on the basis of the double-layered three-dimensional multiband Hubbard model with spin-orbit interaction. In our model, lattice distortion is implemented as the modulation of transfer integrals or a crystal field. The most stable states are estimated within the unrestricted Hartree-Fock approximation, in which the colinear spin configurations with five different spin-quantization axes are adopted as candidates. The obtained spin structures for some particular lattice distortions are consistent with the neutron diffraction results for Ca3Ru2O7. Also, some magnetic phase transitions can occur due to changes in lattice distortion. These results facilitate the comprehensive understanding of the phase diagram of Sr3-xCaxRu2O7.