STM Observation on layered nitride superconductor KxTiNCl

Abstract

Scanning tunneling microscopy (STM) measurements of an α (FeOCl) type layered nitride superconductor Kx TiNCl (x ∼ 0.5) with T c ∼16 K are carried out. STM topographies show clear rectangular-shaped atomic distribution with the periods of ||=0.41 nm and ||=0.33 nm, which correspond to those observed by X-ray measurement. One-dimensional streaky structures are observed at negative biases, which is considered to be arising from N 2p - Ti 3d hybrid bands of the TiN double layers. Both negative and positive STM topographies exhibit the enhanced inhomogeneous background, which can be attributed to the intercalated potassium and/or doped carrier. © 2009 IOP Publishing Ltd.