(color online) Schematic diagrams illustrating the pseudocubic band-convergence, showing (a) crystal structure and schematic electronic bands of cubic zinc blende structure, and (b) crystal structure and schematic electronic bands of ternary chalcopyrites. The c and a are the lattice constants. Γ 4 v is a nondegenerate band, and Γ 5 v is a doubly degenerate band. Δ CF is the crystal field-induced energy split at the top of the Γ 4 v and Γ 5 v bands. The pseudocubic structure has a cubic cation framework with Δ CF embedded in a noncubic distorted anion framework.^[23] Reproduced from Ref. [23] with permission from WILEY-VCH.