Abstract
We have performed the first-principles calculations on to understand electronic structures of the misfit-layered calcium cobaltite, within the generalized gradient approximation. The optimized structure, consisting of a triple rocksalt-type subsystem and a -type subsystem in which their respective octahedra are significantly distorted, shows good agreement with recent experiment. The calculated electronic structures include two-dimensionally dispersive bands across the Fermi energy, which yield the p-type conductivity in the rocksalt subsystem, while the Fermi energy lies in the crystal-field gap of the d states in the subsystem. The spin-polarized calculations show that antiferromagnetic or ferrimagnetic ordering with a small net magnetic moment within the rocksalt subsystem is found to be the ground state, which gives a reasonable explanation of low-temperature behavior of the resistivity and the susceptibility observed in experiment.
- Received 21 January 2002
DOI:https://doi.org/10.1103/PhysRevB.66.155103
©2002 American Physical Society