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Register a new userCorrelation effects on the electronic structure of TiOCl: a NMTO+DMFT study
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Tanusri Saha-Dasgupta
Publication date
2004
fields
Physics
and research's language is
English
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Using the recently developed N-th order muffin-tin orbital-based downfolding technique in combination with the Dynamical Mean Field theory, we investigate the electronic properties of the much discussed Mott insulator TiOCl in the undimerized phase. Inclusion of correlation effects through this approach provides a description of the spectral function into an upper and a lower Hubbard band with broad valence states formed out of the orbitally polarized, lower Hubbard band. We find that these results are in good agreement with recent photo-emission spectra.
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We study the optical properties of the layered rhodium oxide K0.49RhO2, which is isostructural to the thermoelectric material NaxCoO2. The optical conductivity shows broad interband transition peaks as well as a low-energy Drude-like upturn, reminiscent of the optical spectra of NaxCoO2. We find that the peaks clearly shift to higher energies with respect to those of NaxCoO2, indicating a larger crystal-field splitting between eg and t2g bands in K0.49RhO2. The Drude weights suggest that the effective mass of K0.49RhO2 is almost two times smaller than that of NaxCoO2. These differences in electronic structures and correlation effects between NaxCoO2 and K0.49RhO2 are discussed in terms of the difference between Co 3d and Rh 4d orbitals.
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