Angle-resolved photoemission study of PrBa 2 Cu 3 O 7 and PrBa 2 Cu 4 O 8

We have performed an angle-resolved photoemission study on PrBa2Cu307 (Prl23) and PrBa2Cu408 (Prl24) which have hole-doped Cu-O chains. Dispersive features with one-dimensional (ID) character are observed in Prl23 and Prl24 and are attributed to signals from the hole-doped Cu-O chains which are approximately 1/4-filled. While, in Prl23, the ID feature loses its spectral weight near the Fermi level (EF), it crosses EF in Prl24. These results suggest that, while the hole-doped Cu-O single chains in Prl23 have instability to charge ordering, the hole-doped Cu-O double chains in Prl24 can get rid of it.