Aperiodic electronic superstructure in a misfit layered chalcogenide

Abstract

We report STM/STS experiments of(PbSe)_1.16(TiSe₂)₂ and (SnSe)_1.18(TiSe₂)₂. The crystal structure of these materials is layered stacking of octahedral 1T-TiSe₂ layer and rocksalt PbSe/SnSe layer, which are different in symmetry and periodicity. We find that, depending on the termination layers, 2 × 2 CDW found in 1T-TiSe₂ disappears and a new aperiodic electronic superstructure emerges. We ascribe these results to changes in the electronic states induced by charge transfer and bond strength between the layers.