Dresden 2017 – scientific programme

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DS: Fachverband Dünne Schichten

DS 14: 2D Materials Beyond Graphene II (jointly with CPP)

DS 14.10: Talk

Monday, March 20, 2017, 18:15–18:30, REC/PHY C213

Probing the Bandstructure of MoS₂ on Au(111) using Scanning Tunneling Spectroscopy — •Nils Krane, Christian Lotze, and Katharina J. Franke — Freie Universtät Berlin, Berlin, Germany

Transition metal dichalcogenides (TMCD) are two-dimensional materials with a natural band gap, making them interesting as sensors, solar cells or LEDs. Single layer molybdenum disulfide is especially interesting, since it provides a direct band gap [1] and a strong spin-splitting of the valence band at the K-point.

Here we grow MoS₂ epitaxially on a Au(111) surface as described in [2] and investigate it with a combined STM/AFM at low temperatures. Since STS measures the projected LDOS without information of the parallel momentum k_∥ in the Brillouin-Zone, it is not possible to assign a band gap to the K- or Γ-point. To get an insight into the band structure of MoS₂, we measure the decay length κ of the tunneling current, which depends on k_∥ [3]. We find a strong spatial dependence of κ. We ascribe this to the Moiré reconstruction of MoS₂ on Au(111), which differs between fcp- and hcp-stacking at the hollow sides. Furthermore, we investigate the band structure of quasi freestanding MoS₂.

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Sorensen, et al., ACS Nano 8, 6788-6796 (2014)
Zhang, et al., ACS Nano 15, 6494-6500 (2015)