Evidence of line nodes in superconducting gap function in K2Cr3As3 from specific-heat measurements
Abstract
We present low-temperature specific-heat measurements of the quasi-one-dimensional superconductors {K}}2{Cr}}3{As}}3 . Our result shows a sharp specific-heat jump around Tc∼ 6.1 \text{K} with Δ C/γnTc∼ 2.5 , which is much larger than the BCS prediction for a weak-coupling superconductor. It indicates that this superconductor is in the strong-coupling regime. After subtracting the lattice contribution and the Schottky anomaly from the total specific-heat data, the low-temperature electronic specific heat is proportional to T 2 at different fields and also proportional to \sqrt{H} at different temperatures below 2.5 K. These results indicate that line nodes are present in the superconducting gap function of {K}}2{Cr}}3{As}}3 .
- Publication:
-
EPL (Europhysics Letters)
- Pub Date:
- September 2018
- DOI:
- 10.1209/0295-5075/123/57001
- Bibcode:
- 2018EL....12357001S