Absence of density of states transfer observed by interlayer tunneling spectroscopy in magnetic fields forBi2Sr2CaCu2O8+δ

Abstract

Using short-pulse interlayer tunneling spectroscopy, the superconducting gap and the pseudogap structure are measured both in the absence and presence of magnetic fields for slightly overdoped Bi 2 Sr 2 CaCu 2 O 8 + δ . It is found, together with characteristic field-dependent behavior of the superconducting conductance peak, that the tunneling conductance within the superconducting gap remains almost unchanged under magnetic fields up to 9 T. This implies that the transfer of the quasiparticle density of states associated with the superconducting transition is absent in this system, suggesting unconventional pairing interaction or a field-induced ordered state that competes with superconductivity.