Evidence of line nodes in superconducting gap function in K2Cr3As3 from specific-heat measurements

Y. T. Shao; X. X. Wu; L. Wang; Y. G. Shi; J. P. Hu; J. L. Luo

doi:10.1209/0295-5075/123/57001

All issues

Volume 123 / No 5 (September 2018)

EPL, 123 5 (2018) 57001

Abstract

Issue		EPL Volume 123, Number 5, September 2018


Article Number		57001
Number of page(s)		5
Section		Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI		https://doi.org/10.1209/0295-5075/123/57001
Published online		26 September 2018

EPL, 123 (2018) 57001

Evidence of line nodes in superconducting gap function in K₂Cr₃As₃ from specific-heat measurements

Y. T. Shao¹^,2, X. X. Wu¹^,2, L. Wang¹^,2, Y. G. Shi¹^,2, J. P. Hu¹^,2^,3 and J. L. Luo¹^,2^,3^(a)

¹ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences Beijing 100190, China
² School of Physical Sciences, University of Chinese Academy of Sciences - Beijing 100190, China
³ Collaborative Innovation Center of Quantum Matter - Beijing 100190, China

^(a) JLLuo@iphy.ac.cn (corresponding author)

Received: 18 June 2018
Accepted: 29 August 2018

Abstract

We present low-temperature specific-heat measurements of the quasi–one-dimensional superconductors ${\mathrm{K}}_{2}{\mathrm{Cr}}_{3}{\mathrm{As}}_{3}$ . Our result shows a sharp specific-heat jump around $T_{c}\sim 6.1\ \text{K}$ with $\Delta C/\gamma_{n}T_{c}\sim 2.5$ , 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 T² 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 ${\mathrm{K}}_{2}{\mathrm{Cr}}_{3}{\mathrm{As}}_{3}$ .

PACS: 74.25.Bt – Thermodynamic properties / 74.20.Mn – Nonconventional mechanisms / 71.27.+a – Strongly correlated electron systems; heavy fermions

© EPLA, 2018

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