Inverse photoemission study of Bi2Sr2CaCu2O8

Abstract
An inverse photoemission spectrum of Bi2 Sr2 CaCu2 O8 is presented. The spectrum shows a clear Fermi-edge structure in contrast to those reported for YBa2 Cu3 O7 and La1.8 Sr0.2 CuO4, giving direct evidence for the existence of the Fermi-liquid states in Bi2 Sr2 CaCu2 O8.