Jun 20 – 23, 2022
Max Planck Institut für Festkörperforschung
Europe/Berlin timezone

Superconducting collective Leggett modes in single-layer 1H-NbSe2

Jun 20, 2022, 5:30 PM
2D5 (Max Planck Institut für Festkörperforschung)


Max Planck Institut für Festkörperforschung

Contributed Poster Poster Session


Daniel Muñoz-Segovia (Donostia International Physics Center)


While bulk 2H-NbSe2 is generally accepted to be a conventional superconductor, several unconventional features of the superconducting state have been reported in the monolayer limit, including the breaking of threefold symmetry in magnetotransport [1,2] and anomalously large in-plane critical fields [3]. In this work, I will first present another unconventional feature measured by our collaborators [4]: the existence of satellite peaks in the STM spectra of 1H-NbSe2 monolayers which exist only in the superconducting state and show a clear anticorrelation with the superconducting gap. After briefly discussing other potential candidate explanations, I will propose a scenario of competing pairing between s-wave and subleading f-wave triplet channels that leads to a superconducting Leggett collective mode. In particular, I will present a calculation of the Leggett mode energy using a simplified continuum model for NbSe2, and show that this particle-particle collective mode gives rise to resonances in the tunneling spectrum. I will discuss how our model compares with the experimental data, discuss the origin of the anticorrelation, and argue that it provides support to the competing pairing scenario, with a sizable attraction in the subleading triplet channel.

[1] A. Hamill, et al., Nat. Phys. 17, 949–954 (2021).
[2] C.-W. Cho, et al., arXiv:2003.12467 (2020).
[3] M. Kuzmanović, et al., arXiv:2104.00328 (2021).
[4] W. Wan, et al., arXiv:2101.04050 (2021).

Primary author

Daniel Muñoz-Segovia (Donostia International Physics Center)


Dr Wen Wan (Donostia International Physics Center) Dr Paul Dreher (Donostia International Physics Center) Dr Rishav Harsh (Donostia International Physics Center) Prof. Francisco Guinea (IMDEA Nanoscience, Donostia International Physics Center) Dr Fernando de Juan (Donostia International Physics Center, Ikerbasque (Basque Foundation for Science)) Dr Miguel Ugeda (Donostia International Physics Center, Centro de Física de Materiales, Ikerbasque (Basque Foundation for Science))

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