Evidence of nodal superconductivity in monolayer 1H-TaS$_2$ with hidden order fluctuations

Viliam Vaňo; Somesh Chandra Ganguli; Mohammad Amini; Linghao Yan; Maryam Khosravian; Guangze Chen; Shawulienu Kezilebieke; Jose L. Lado; Peter Liljeroth

doi:10.1002/adma.202305409

arXiv · 2112.07316

Evidence of nodal superconductivity in monolayer 1H-TaS$_2$ with hidden order fluctuations

Viliam Vaňo·Somesh Chandra Ganguli·Mohammad Amini·Linghao Yan·Maryam Khosravian·Guangze Chen·Shawulienu Kezilebieke·Jose L. Lado·Peter Liljeroth

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Abstract

Unconventional superconductors represent one of the fundamental directions in modern quantum materials research. In particular, nodal superconductors are known to appear naturally in strongly correlated systems, including cuprate superconductors and heavy-fermion systems. Van der Waals materials hosting superconducting states are well known, yet nodal monolayer van der Waals superconductors have remained elusive. Here, using low-temperature scanning tunneling microscopy (STM) and spectroscopy (STS) experiments, we show that pristine monolayer 1H-TaS$_2$ realizes a nodal superconducting state. By including non-magnetic disorder, we drive the nodal superconducting state to a conventional gapped s-wave state. Furthermore, we observe the emergence of many-body excitations close to the gap edge, signalling a potential unconventional pairing mechanism. Our results demonstrate the emergence of nodal superconductivity in a van der Waals monolayer, providing a building block for van der Waals heterostructures exploiting unconventional superconducting states.

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Viliam Vaňo, Somesh Chandra Ganguli, Mohammad Amini, Linghao Yan, Maryam Khosravian, Guangze Chen, Shawulienu Kezilebieke, Jose L. Lado, Peter Liljeroth. 2021-12-14. Evidence of nodal superconductivity in monolayer 1H-TaS$_2$ with hidden order fluctuations. https://doi.org/10.1002/adma.202305409

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