PHOTOEMISSION STUDY OF QUASI-ONE-DIMENSIONAL HALOGEN-BRIDGED COMPOUND [Ni(chxn)2Br]Br2

Abstract

We report results of the angle-resolved photoemission experiments on a quasi-one-dimensional halogen-bridged complex [Ni(chxn) 2 Br]Br 2 ( chxn = 1R, 2R-cyclohexanediamine), which is a one-dimensional Heisenberg spin chain with S = 1/2 and J ~ 3600 K . The expected two dispersions, originated with spin–charge separations as have been observed in other quasi-one-dimensional electron systems like Sr 2 CuO 3, are not clearly observed in this compound. Instead, only one 'band" having about 0.5 eV energy dispersion is found in the half of the Brillouin zone.