Optimized superconductivity in the vicinity of a nematic quantum critical point in the kagome superconductor Cs(V<sub>1-x</sub>Ti<sub>x</sub>)<sub>3</sub>Sb<sub>5</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37414793.
- Also identified by DOI 10.1038/s41467-023-39495-1 and PMC identifier 10326258.
- 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
CsV<sub>3</sub>Sb<sub>5</sub> exhibits superconductivity at T<sub>c</sub> = 3.2 K after undergoing intriguing two high-temperature transitions: charge density wave order at ~98 K and electronic nematic order at T<sub>nem</sub> ~ 35 K. Here, we investigate nematic susceptibility in single crystals of Cs(V<sub>1-x</sub>Ti<sub>x</sub>)<sub>3</sub>Sb<sub>5</sub> (x = 0.00-0.06) where double-dome-shaped superconducting phase diagram is realized. The nematic susceptibility typically exhibits the Curie‒Weiss behaviour above T<sub>nem</sub>, which is monotonically decreased with x. Moreover, the Curie‒Weiss temperature is systematically suppressed from ~30 K for x = 0 to ~4 K for x = 0.0075, resulting in a sign change at x = ~0.009. Furthermore, the Curie constant reaches a maximum at x = 0.01, suggesting drastically enhanced nematic susceptibility near a putative nematic quantum critical point (NQCP) at x = ~0.009. Strikingly, T<sub>c</sub> is enhanced up to ~4.1 K with full Meissner shielding realized at x = ~0.0075-0.01, forming the first superconducting dome near the NQCP. Our findings directly point to a vital role of nematic fluctuations in enhancing the superconducting properties of Cs(V<sub>1-x</sub>Ti<sub>x</sub>)<sub>3</sub>Sb<sub>5</sub>.