Closing of the Mott gap near step edges in NiS2

Abstract

A prototypical charge-transfer type Mott insulator NiS2 pyrite exhibits a metal-insulator transition with bandwidth control. Recent discoveries on surface-specific electronic states on other 3d transition-metal disulfide pyrites motivate us to further investigate the surface of NiS2, where metallic surface conduction is discussed. Here, the spectroscopic-imaging scanning-tunneling-microscopy observations revealed that the surface is not metallic, contrary to the expectation. Instead, the Mott gap is closed near step edges, suggesting possible electrical conduction from one-dimensional channels. The edge anomaly was observed irrespective of its magnetic order and is limited to the insulator phases.

arXiv comment5 pages, 5 figures

References in corpus (10)

• Realization of Quantum Spin Hall State in Monolayer 1T'-WTe2
• Higher-Order Topology in Bismuth
• High-throughput calculations of magnetic topological materials
• Room-temperature quantum spin Hall edge state in a higher-order topological insulator Bi${}_4$Br${}_4$
• Discovery of charge order and corresponding edge state in kagome magnet FeGe
• Direct observation of the bandwidth control Mott transition in the NiS${}_{2-x}$Se${}_x$ multiband system
• Metal-insulator Crossover Behavior at the Surface of NiS_2
• Surface effects on the Mott-Hubbard transition in archetypal V${}_2$O${}_3$
• Atomic Diffusion in the Surface State of Mott Insulator NiS2
• Structural investigation of the insulator-metal transition in NiS${}_{2-x}$Se${}_x$ compounds