Interplay among Spin, Orbital and Lattice Degrees of Freedom int2gElectron Systems with Edge-Sharing Network of Octahedra

Transition metal oxides whose lattice structure has edge-sharing network ofoctahedra constitute a diverse group of intriguing materials besides compoundswith corner-sharing octahedra such as perovskites. We present a theoreticalinvestigation of the interplay among spin, orbital and lattice degrees offreedom in these materials. We focus on $t_{2g}$ electron systems where a keencompetition among those degrees of freedom is expected to emerge under arelatively weak Jahn-Teller coupling. We study the interplay between spin andorbital degrees of freedom in vanadium spinels and titanium pyroxenes. Weclarify the important role of the strong anisotropy in the orbital interactionsdue to the edge-sharing geometry. We also discuss the interplay between spinand lattice in chromium spinels focusing on the magnetization process under theexternal magnetic field.Comment: 5 pages, 2 figures, proceedings submitted to QSS0