Sr3(Ru1-xMnx)2O7, in which 4d-Ru is substituted by the more localized 3d-Mn, is studied by x-ray dichroism and spin-resolved density functional theory. We find that Mn impurities do not exhibit the same 4+ valence of Ru, but act as 3+ acceptors; the extra eg electron occupies the in-plane 3dx2-y2 orbital instead of the expected out-of-plane 3d3z2-r2. We propose that the 3d-4d interplay, via the ligand oxygen orbitals, is responsible for this crystal-field level inversion and the material's transition to an antiferromagnetic, possibly orbitally-ordered, low-temperature state.
@article{arxiv.0801.2995,
title = {Crystal-field level inversion in lightly Mn-doped Sr3Ru2O7},
author = {M. A. Hossain and Z. Hu and M. W. Haverkort and T. Burnus and C. F. Chang and S. Klein and J. D. Denlinger and H. -J. Lin and C. T. Chen and R. Mathieu and Y. Kaneko and Y. Tokura and S. Satow and Y. Yoshida and H. Takagi and A. Tanaka and I. S. Elfimov and G. A. Sawatzky and L. H. Tjeng and A. Damascelli},
journal= {arXiv preprint arXiv:0801.2995},
year = {2008}
}
Comments
A high-resolution version can be found at http://www.physics.ubc.ca/~quantmat/ARPES/PUBLICATIONS/Articles/MnSr3Ru2O7_XAS.pdf