Рубрики:
OPTICAL-ABSORPTION
PHASE-DIAGRAM
CUGEO3
SPECTRUM
SUPERCONDUCTORS
EXCITATIONS
SR2CUO2CL2
SCATTERING
LA2CUO4
CUPRATE
OPTICAL-ABSORPTION
PHASE-DIAGRAM
CUGEO3
SPECTRUM
SUPERCONDUCTORS
EXCITATIONS
SR2CUO2CL2
SCATTERING
LA2CUO4
CUPRATE
Аннотация: We present and analyze high-resolution alpha-, sigma-, and pi-polarized absorption spectra related to d-d electronic transitions in tetragonal metaborate CuB2O4 where copper Cu2+ ions occupy two crystallographically distinct 4b and 8d positions. The spectra are characterized by exceptionally rich fine structure in the spectral range of 1.4-2.4 eV. Six zero-phonon (ZP) lines originating from the electronic transitions within the Cu2+ ions in both positions are distinguished and identified. Symmetry analysis explains polarization properties of the ZP lines in the 8d positions but only partially explains them in the 4b positions. Reliable assignment of all six ZP lines to specific transitions allowed us to calculate genuine cubic Dq and tetragonal Ds and Dt crystal-field parameters for both positions. We show that the (3r(2) - z(2)) state, the energy of which is the measure of the Jahn-Teller splitting, is the highest 3d state for both types of Cu2+ ion positions. Using the obtained crystal-field parameters as the reference values, we estimated Dq, Ds, and Dt for several other cuprates with different Cu-O bond lengths. In particular, the 3d level splitting in La2CuO4, Nd2CuO4, CuGeO3, Sr2CuO2Cl2, and Cu3B7O13Cl was analyzed. Our estimates suggest that the Jahn-Teller splitting in some of these cuprates is larger than it was assumed previously.
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Держатели документа:
[Pisarev, R. V.
Kalashnikova, A. M.] Russian Acad Sci, AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia
[Schoeps, O.] Dortmund Tech Univ, Inst Phys, D-44221 Dortmund, Germany
[Bezmaternykh, L. N.] Russian Acad Sci, Siberian Branch, Inst Phys, Krasnoyarsk 660036, Russia
ИФ СО РАН
Ioffe Physical-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russian Federation
Institute of Physics, Dortmund Technical University, 44221 Dortmund, Germany
Institute of Physics, Siberian Branch, Russian Academy of Sciences, 660036 Krasnoyarsk, Russian Federation
Доп.точки доступа:
Pisarev, R. V.; Kalashnikova, A. M.; Schops, O.; Bezmaternykh, L. N.; Безматерных, Леонард Николаевич