Using controlled disorder to probe the interplay between charge order and superconductivity in NbSe<sub>2</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30022110.
- Also identified by DOI 10.1038/s41467-018-05153-0 and PMC identifier 6052160.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The interplay between superconductivity and charge-density wave (CDW) in 2H-NbSe<sub>2</sub> is not fully understood despite decades of study. Artificially introduced disorder can tip the delicate balance between two competing long-range orders, and reveal the underlying interactions that give rise to them. Here we introduce disorder by electron irradiation and measure in-plane resistivity, Hall resistivity, X-ray scattering, and London penetration depth. With increasing disorder, the superconducting transition temperature, T<sub>c</sub>, varies non-monotonically, whereas the CDW transition temperature, T<sub>CDW</sub>, monotonically decreases and becomes unresolvable above a critical irradiation dose where T<sub>c</sub> drops sharply. Our results imply that the CDW order initially competes with superconductivity, but eventually assists it. We argue that at the transition where the long-range CDW order disappears, the cooperation with superconductivity is dramatically suppressed. X-ray scattering and Hall resistivity measurements reveal that the short-range CDW survives above the transition. Superconductivity persists to much higher dose levels, consistent with fully gapped superconductivity and moderate interband pairing.