We have performed angle-resolved photoemission spectroscopy of Na xCoO2 (x=0.65 and 0.77) to clarify the origin of antiferromagnetic (AF) transition. We determined the electronic band structure along the out-of-plane direction by varying photon energy, and revealed that a three-dimensional electron pocket emerges at Γ point in the AF sample (x=0.77) while it is absent in the non-AF counterpart (x=0.65), showing the transition of Fermi-surface topology with the band filling. The present result suggests that the emergence of the electron pocket is closely related to the various anomalies of the physical properties in Na-rich cobaltates.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2010 Mar 22|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics