Pressure-dependent electronic structures in multiferroic DyMnO3: A combined lifetime-broadening-suppressed x-ray absorption spectroscopy and ab initio electronic structure study

National Synchrotron Radiation Research Center (NSRRC), Hsinchu 30076, Taiwan, Republic of China.
The Journal of Chemical Physics (Impact Factor: 2.95). 10/2010; 133(15):154510. DOI: 10.1063/1.3490400
Source: PubMed


Variations in the electronic structure and structural distortion in multiferroic DyMnO(3) were probed by synchrotron x-ray diffraction, lifetime-broadening-suppressed x-ray absorption spectroscopy (XAS), and ab initio electronic structure calculations. The refined x-ray diffraction data enabled an observation of a diminished local Jahn-Teller distortion of Mn sites within MnO(6) octahedra in DyMnO(3) on applying the hydrostatic pressure. The intensity of the white line in Mn K-edge x-ray absorption spectra of DyMnO(3) progressively increased with the increasing pressure. With the increasing hydrostatic pressure, the absorption threshold of an Mn K-edge spectra of DyMnO(3) shifted toward a greater energy, whereas the pre-edge line slightly shifted to a smaller energy. We provide the spectral evidence for the pressure-induced bandwidth broadening for manganites. The intensity enhancement of the white line in Mn K-edge spectra is attributed to a diminished Jahn-Teller distortion of MnO(6) octahedra in compressed DyMnO(3). A comparison of the pressure-dependent XAS spectra with the ab initio electronic structure calculations and full calculations of multiple scattering using the code FDMNES shows the satisfactory agreement between experimental and calculated Mn K-edge spectra.

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