Structural features and transport properties of iodine intercalated misfit layer [BiCaO2]2[CoO2]1.69 single crystals

The thermopower and the electrical resistivity of [BiCaO₂]₂[CoO₂]_1.69 and corresponding iodine intercalated single crystals have been measured. Upon intercalation, the thermopower is drastically decreased, indicating that there is a hole doping by charge transfer from the intercalated iodine layer to the hexagonal CoO₂ layer. The resistivity is increased due to stacking faults and disordered structures. Structural analyses confirmed the stacking scheme along the c direction, with the localisation of iodine between the [BiO] double layers. The effect of intercalation on the thermoelectric properties suggested discussions from the view point of hole doping and nano-block layer coupling effect.