Angle-Resolved Photoemission Study of Insulating and Metallic Cu-O Chains in PrBa 2 Cu 3 O 7 and PrBa 2 Cu 4 O 8

摘要: We compare the angle-resolved photoemission spectra of hole-doped Cu-O chains in ${\mathrm{PrBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7}$ (Pr123) and ${\mathrm{PrBa}}_{2}{\mathrm{Cu}}_{4}{\mathrm{O}}_{8}$ (Pr124). While, Pr123, a dispersive feature from chain takes band maximum at ${k}_{b}$ (momentum along chain) $\ensuremath{\sim}\ensuremath{\pi}/4$ loses its spectral weight around Fermi level, it reaches level ${k}_{b}\ensuremath{\sim}\ensuremath{\pi}/4$ Pr124. Although Pr123 Pr124 are approximately 1/4 filled, they show contrasting behaviors: While have an instability to charge ordering, those avoid interesting metallic coupled-chain system.