Unraveling electronic-structure features for metallic Na0.33CoO2 and charge-ordered Na0.5CoO2 by high-resolution electron energy-loss spectroscopy

2006/12/07 by Ruijuan Xiao, J. H. Chen, Xiao, R. J. +11
Chemical Engineering · Energy · Materials Science · #Catalysis and Oxidation Reactions #Electrocatalysts for Energy Conversion #Electronic and Structural Properties of Oxides #FOS: Physical sciences #Strongly Correlated Electrons (cond-mat.str-el)

paper · pdf · doi:10.48550/arxiv.cond-mat/0612183

openalex publication_date 2006/12/07 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28

Abstract

Measurements by high-resolution electron energy-loss spectroscopy (HREELS) of NaxCoO2 reveal spectral features that differ remarkably between the metallic Na0.33CoO2 and the charge-ordered insulator Na0.5CoO2. Calculations by density functional theory plus Hubbard U (DFT+U) demonstrate that these differences arise essentially from the relatively greater strength of electron correlation in addition to the crystal-field effect in Na0.5CoO2. The effective U values are estimated to be ~3.0eV for x=0.5 and ~1.0eV for x=0.33, respectively. The electronic structures for these correlation strengths give good interpretations for the physical properties observed in the materials.

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