Mini bands in MoS2 moiré superlattices

What is it about?

The exotic correlated phases that emerge in the low-dispersing moiré bands of twisted van der Waals structures have opened new exciting opportunities in condensed-matter physics. These systems exhibit a rich phase diagram of novel physical phenomena and exotic correlated phases that emerge in the low-dispersing bands. Despite its popularity, the resulting mini-bands in the conduction band of MoS2 moiré superlattices remained elusive so far. In this work, we resolve these spin-valley mini-bands via transport spectroscopy in micron-scale devices. The theoretical energy scales exhibit an astounding agreement with our experimental observations, which together with the behavior under thermal activation, suggest an electronic phase transition. These intriguing observations highlight the potential of twisted MoS2 structures as a playground to explore correlated electron states and associated phenomena.

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Why is it important?

The conduction band of MoS2 moiré superlattices are probed here. Due to difficulty in contact fabrication, this has been hard to achieve. We were able to use the tunnelling through the Schottky contacts to shed light into these mini-bands. We also see signatures of spin-valley degeneracy breaking in the system signalling correlations. This is the first observation of such an effect in MoS2.

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