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Synthetic Semimetals with van der Waals Interfaces

Published in Nano letters. 2020, vol. 20, no. 2, p. 1322-1328
Abstract The assembly of suitably designed van der Waals (vdW) heterostructures represents a new approach to produce artificial systems with engineered electronic properties. Here, we apply this strategy to realize synthetic semimetals based on vdW interfaces formed by two different semiconductors. Guided by existing ab initio calculations, we select WSe2 and SnSe2 mono- and multilayers to assemble vdW interfaces and demonstrate the occurrence of semimetallicity by means of different transport experiments. Semimetallicity manifests itself in a finite minimum conductance upon sweeping the gate over a large range in ionic liquid gated devices, which also offer spectroscopic capabilities enabling the quantitative determination of the band overlap. The semimetallic state is additionally revealed in Hall effect measurements by the coexistence of electrons and holes, observed by either looking at the evolution of the Hall slope with sweeping the gate voltage or with lowering temperature. Finally, semimetallicity results in the low-temperature metallic conductivity of interfaces of two materials that are themselves insulating. These results demonstrate the possibility to implement a state of matter that had not yet been realized in vdW interfaces and represent a first step toward using these interfaces to engineer topological or excitonic insulating states.
Keywords Van der Waals heterostructuresSemimetalBand overlapIonic liquid gating2D materials
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Other version: https://pubs.acs.org/doi/10.1021/acs.nanolett.9b04810
Research group Groupe Morpurgo
Swiss National Science Foundation: Division II
Autre: Graphene Flagship
(ISO format)
REDDY, Bojja Aditya et al. Synthetic Semimetals with van der Waals Interfaces. In: Nano Letters, 2020, vol. 20, n° 2, p. 1322-1328. doi: 10.1021/acs.nanolett.9b04810 https://archive-ouverte.unige.ch/unige:129467

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Deposited on : 2020-01-28

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