Tunnelling spectroscopy of gate-induced superconductivity in MoS2


The ability to gate-induce superconductivity by electrostatic charge accumulation is a recent breakthrough in physics and nanoelectronics. With the exception of LaAlO3/SrTiO3 interfaces, experiments on gate-induced superconductors have been largely confined to resistance measurements, which provide very limited information about the superconducting state. Here, we explore gate-induced superconductivity in MoS2 by performing tunnelling spectroscopy to determine the energy-dependent density of states (DOS) for different levels of electron density n. In the superconducting state, the DOS is strongly suppressed at energy smaller than the gap Δ, which is maximum (Δ ~2 meV) for n of ~1 × 1014 cm−2 and decreases monotonously for larger n. A perpendicular magnetic field B generates states at E < Δ that fill the gap, but a 20% DOS suppression of superconducting origin unexpectedly persists much above the transport critical field. Conversely, an in-plane field up to 10 T leaves the DOS entirely unchanged. Our measurements exclude that the superconducting state in MoS2 is fully gapped and reveal the presence of a DOS that vanishes linearly with energy, the explanation of which requires going beyond a conventional, purely phonon-driven Bardeen–Cooper–Schrieffer mechanism.

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Fig. 1: Nanofabricated MoS2 devices for tunnelling spectroscopy measurements.
Fig. 2: Temperature evolution of the bias-dependent tunnelling conductance.
Fig. 3: Investigating the nature of the superconducting state in MoS2.
Fig. 4: Magnetic field dependence of the tunnelling DOS.

Change history

  • 17 May 2018

    In the version of this Article originally published, an error during typesetting led to the curve in Fig. 2a being shifted to the right, and the curves in the inset of Fig. 2a being displaced. The figure has now been corrected in all versions of the Article; the original and corrected Fig. 2a are shown below.


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The authors acknowledge A. Ferreira for continued technical support of the experiments. The authors also thank K.T. Law for extended and extremely useful discussions. Financial support from the Swiss National Science Foundation, the NCCR QSIT and the EU Graphene Flagship project is acknowledged.

Author information

D.C., H.Z. and B.A.R. fabricated the devices and performed electrical measurements. D.C. and H.Z. analysed the data. H.B. provided high-quality MoS2 crystals. A.F.M. conceived the experiment, directed the research and wrote the manuscript. All authors read the manuscript and provided comments.

Correspondence to Alberto F. Morpurgo.

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Supplementary text and Supplementary Figures 1–7

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Costanzo, D., Zhang, H., Reddy, B.A. et al. Tunnelling spectroscopy of gate-induced superconductivity in MoS2. Nature Nanotech 13, 483–488 (2018). https://doi.org/10.1038/s41565-018-0122-2

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