Abstract
O K - and Mn L 2,3 -edges x-ray absorption spectra of orthorhombic TbMnO3 single crystals show strong polarization dependence, in contrast with results of previous experiments on orthorhombic LaMnO 3 and DyMnO 3 thin films that show nearly isotropic spectral structure. First-principles calculations reveal that TbMnO 3 exhibits a zigzag e g orbital ordering ground state. The highly distorted MnO6 octahedron and orbital ordering in TbMnO 3 produce highly anisotropic Mn-O bonding within the ab plane, a frustration of the magnetic ordering, and the formation of complicated incommensurate magnetic structures. © 2009 American Institute of Physics.