Crystal-Field Level Inversion in Lightly Mn-Doped Sr$_3$Ru$_2$O$_7$
ORAL
Abstract
Sr$_3$(Ru$_{1-x}$Mn$_x$)$_2$O$_7$, in which 4$d$-Ru is substituted by the more localized 3$d$-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 $e_g$ electron occupies the in-plane $3d_{x^2-y^2}$ orbital instead of the expected out-of-plane $3d_{3z^2-r^2}$. We propose that the 3$d$-4$d$ 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. Published: Phys. Rev. Lett. 101, 016404 (2008).
*ALS Doctoral Fellowship, LBNL, Berkeley
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