Moiré structure of MoS2 on Au(111): Local structural and electronic properties

Abstract

Monolayer islands of molybdenum disulfide (MoS2) on Au(111) form a characteristic moiré structure, leading to locally different stacking sequences at the S-Mo-S-Au interface. Using lowtemperature scanning tunneling microscopy (STM) and atomic force microscopy (AFM), we find that the moiré islands exhibit a unique orientation with respect to the Au crystal structure. This indicates a clear preference of MoS2 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 and the identification of the origin of the states from different areas in the Brillouin zone.

Comprehensive tunneling spectroscopy of quasifreestanding MoS2 on graphene on Ir(111)

“…As discussed, we could not unambiguously detect the K-point states which represent the VBM of ML-MoS 2 , presumably due to their short decay length, in-plane orbital character, and proximity to the dominating Γ point. States being hidden due to a combination of these factors is an issue; previous comprehensive STS investigations of ML-MoS 2 have also failed to identify the VBM [28]. The K-point VBM was clearly detected in ML-MoSe 2 and ML-WSe 2 , presumably because in these cases it is separated from the Γ-point by large energies of 0.39 eV and 0.64 eV respectively [26].…”

“…In collaborative STS [17] and ARPES [8] investigation of ML-MoS 2 on Au(111), discrepancies of 0.10 eV and 0.15 eV were found for the Γ-and K-point respectively. Comprehensive STS on the same system showed further disagreement [28]. A comparative study of comprehensive STS and ARPES (performed on the same sample in the same UHV chamber) would present a considerable experimental challenge, but would be worthwhile if the community is to address these problems of inconsistency.…”

Monolayers of MoS2 on Ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of TCNQ

“…−1.55 V. The strong features in the dI/dV spectra are associated to the onset of specific bands, which are labeled by Q, Γ 1 and Γ 2 according to their location in the Brillouin zone. The assignment follows that in [38]. pattern bears a topographic and an electronic modulation [38], we investigate the differential conductance (dI/dV) spectra on different locations ( Figure 1d).…”

“…The assignment follows that in [38]. pattern bears a topographic and an electronic modulation [38], we investigate the differential conductance (dI/dV) spectra on different locations ( Figure 1d). We first examine the spectrum on the top site of the moiré structure.…”

Mapping the perturbation potential of metallic and dipolar tips in tunneling spectroscopy on MoS2

“…A monolayer of MoS 2 was grown on a clean Au(111) surface by deposition of Mo and subsequent heating in an H 2 S atmosphere 25,26 . BTTT molecules were evaporated from a Knudsen cell evaporator (365 K) onto the sample held at 200 K. All STM measurements were carried out at arXiv:1906.07820v1 [cond-mat.mes-hall] 18 Jun 2019 24 (1 V/20 pA).…”