Stacking faults and metallic properties of triangular lattice CoO_{2} with a threelayer structure
Abstract
A triangular lattice system CoO_{2} is synthesized through chemical extraction of Li from LiCoO_{2} with H_{2}SO_{4}. On the basis of the xray powder diffraction and various composition analyses, the structure approximately modelled with space group R\overline {3}m and cell dimensions a = 2.8388(6) and c = 13.439(1) Å in the hexagonal basis has three oxygen layers with a prismatic oxygen environment (P3) between the layers. It also has stacking faults with shift vectors \bi {s}_{1}=\frac
{2}{3}\bi {a}+\frac {1}{3}\bi {b} and \bi {s}_{2}=\frac {1}{3}\bi {a}+\frac {2}{3}\bi {b} along the shift of \frac {1}{3}\bi {c} . Through measurements of the thermoelectric power and magnetic susceptibility, CoO_{2} (P3) is suggested to be a weakly correlated metal with a mass enhancement of 2.6. Na_{0.09}CoO_{2} synthesized through Na extraction from Na_{0.7}CoO_{2} also shows metallic properties with correlation effects probably stronger than those of CoO_{2} (P3).
 Publication:

Journal of Physics Condensed Matter
 Pub Date:
 April 2008
 DOI:
 10.1088/09538984/20/17/175207
 Bibcode:
 2008JPCM...20q5207O