First-Principles Computation of YVO_3 : Combining Path-Integral Renormalization Group with Density-Functional Approach(Condensed matter: electronic structure and electrical, magnetic, and optical properties)

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We investigate the electronic structure of the transition-metal oxide YVO_3 by a hybrid first-principles scheme. The density-functional theory with the local-density-approximation by using the local muffin-tin orbital basis is applied to derive the whole band structure. The electron degrees of freedom far from the Fermi level are eliminated by a down folding procedure leaving only the V 3d t_<2g> Wannier band as the low-energy degrees of freedom, for which a low-energy effective model is constructed. This low-energy effective Hamiltonian is solved exactly by the path-integral renormalization group method. It is shown that the ground state has the G-type spin and the C-type orbital ordering in agreement with experimental indications. The indirect charge gap is estimated to be around 0.7eV, which prominently improves the previous estimates by other conventional methods.
社団法人日本物理学会の論文
2006-12-15