Moir\'e structure of MoS$_2$ on Au(111): Local structural and electronic properties

TL;DR

This study investigates the moiré pattern and local electronic properties of monolayer MoS₂ on Au(111), revealing preferred stacking orientations and how local atomic structures influence electronic band features.

Contribution

It provides detailed atomic-scale imaging and electronic characterization of MoS₂ on Au(111), highlighting the relationship between moiré structures and electronic properties with a focus on local stacking effects.

Findings

Moiré islands show a preferred orientation relative to Au(111).

Local atomic structure affects valence and conduction band features.

Tunneling decay constants vary with bias voltage, indicating different electronic states.

Abstract

Monolayer islands of molybdenum disulfide (MoS$_2$) on Au(111) form a characteristic moir\'e structure, leading to locally different stacking sequences at the S-Mo-S-Au interface. Using low-temperature scanning tunneling microscopy (STM) and atomic force microscopy (AFM), we find that the moir\'e islands exhibit a unique orientation with respect to the Au crystal structure. This indicates a clear preference of MoS$_2$ growth in a regular stacking fashion. We further probe the influence of the local atomic structure on the electronic properties. Differential conductance spectra show pronounced features of the valence band and conduction band, some of which undergo significant shifts depending on the local atomic structure. We also determine the tunneling decay constant as a function of the bias voltage by a height-modulated spectroscopy method. This allows for an increased sensitivity of states with non-negligible parallel momentum $k_\parallel$ and the identification of the origin of the states from different areas in the Brillouin zone.