Tunneling spectroscopy of gate-induced superconductivity in MoS$_2$

Davide Costanzo; Haijing Zhang; Bojja Aditya Reddy; Helmuth Berger; Alberto F. Morpurgo

doi:10.1038/s41565-018-0122-2

paper

Tunneling spectroscopy of gate-induced superconductivity in MoS $_{2}$

arXiv:1806.03222 · doi:10.1038/s41565-018-0122-2

Abstract

The ability to gate-induce superconductivity by electrostatic charge accumulation is a recent breakthrough in physics and nano-electronics. With the exception of LaAlO $_{3}$ /SrTiO $_{3}$ 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 MoS $_{2}$ by performing tunneling 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 ~ 10 $^{14}$ 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 MoS $_{2}$ 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.

Tunneling spectroscopy of gate-induced superconductivity in MoS $_{2}$

Abstract

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Cited by in corpus (37)

Tunneling spectroscopy of gate-induced superconductivity in MoS2​

Abstract

References in corpus (24)

Cited by in corpus (37)

Tunneling spectroscopy of gate-induced superconductivity in MoS $_{2}$