Browsing by Author "Rao, S. M."

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Orbital polarization of the unoccupied states in multiferroic LiCu(2)O(2)
(2008-12-01)
Chen, C. L.
;
Yeh, K. W.
;
Huang, D. J.
;
Hsu, F. C.
;
Lee, Y. C.
Using measurements of polarization-dependent soft-x-ray absorption and band-structure calculations including the on-site Coulomb interaction, we investigated the symmetry of the intrinsic 3d holes in the low-dimensional quantum magnet LiCu(2)O(2) with edge-sharing spin chains. The Cu L-edge and O K-edge measurements with in-plane and out-of-plane E vectors of x ray reveal the orbital character of the valence states of Cu on different sites. The unoccupied 3d states of nominal Cu(2+) exhibit predominantly xy symmetry, whereas 3d holes of 3z(2)-r(2) symmetry reside on the nominal Cu(+) sites. Both the experimental observations and theoretical calculations agree on the hybridization of the O 2p and Cu 3d states above the Fermi level. The existence of 3d holes on Cu(+) enhances the interlayer magnetic coupling.
Orbital polarization of the unoccupied states in multiferroic LiCu2O2
(2008-12-01)
Chen, C. L.
;
Yeh, K. W.
;
Huang, D. J.
;
Hsu, F. C.
;
Lee, Y. C.
Using measurements of polarization-dependent soft-x-ray absorption and band-structure calculations including the on-site Coulomb interaction, we investigated the symmetry of the intrinsic 3d holes in the low-dimensional quantum magnet LiCu2O2 with edge-sharing spin chains. The Cu L-edge and O K-edge measurements with in-plane and out-of-plane E vectors of x ray reveal the orbital character of the valence states of Cu on different sites. The unoccupied 3d states of nominal Cu2+ exhibit predominantly xy symmetry, whereas 3d holes of 3z(2)-r(2) symmetry reside on the nominal Cu+ sites. Both the experimental observations and theoretical calculations agree on the hybridization of the O 2p and Cu 3d states above the Fermi level. The existence of 3d holes on Cu+ enhances the interlayer magnetic coupling.