Figure 5.

(a) Total and partial density of states (PDOS) calculated using LSDA+U. The PDOS is projected onto the Ca, Cu, Ti, and O atoms. (b) PDOS projected onto the d_xy and the sum of the other four d orbitals of the Cu atom coordinated to O atoms in the xy plane, as shown in the inset figure. Spin-up and spin-down electrons are shown separately above and below the x-axis. (c) Band structure of CaCu₃Ti₄O₁₂ calculated using the LSDA+U method. Note that, with antiferromagnetic ordering, the separate spin channels have identical band structures. Dots are added to the bands to show the projection of the states onto orbitals centered at different atoms, the radius of the dot is proportional to the extent of overlap. The dots are colored according to projections onto the Ca (green), Cu (blue), Ti (pink), and O (red) atoms.