Title: Resonances in the Field-Angle-Resolved Thermal Conductivity of ${\mathrm{CeCoIn}}_5$

Abstract

Here, the thermal conductivity measurement in a rotating magnetic field is a powerful probe of the structure of the superconducting energy gap. We present high-precision measurements of the low-temperature thermal conductivity in the unconventional heavy-fermion superconductor CeCoIn₅, with the heat current J along the nodal [110] direction of its d_x²–y² order parameter and the magnetic field up to 7 T rotating in the ab plane. In contrast to the smooth oscillations found previously for J∥[100], we observe a sharp resonancelike peak in the thermal conductivity when the magnetic field is also in the [110] direction, parallel to the heat current. We explain this peak qualitatively via a model of the heat transport in a d-wave superconductor. In addition, we observe two smaller but also very sharp peaks in the thermal conductivity for the field directions at angles Θ≈±33° with respect to J. The origin of the observed resonances at Θ≈±33° at present defies theoretical explanation. The challenge of uncovering their source will dictate exploring theoretically more complex models, which might include, e.g., fine details of the Fermi surface, Andreev bound vortex core states, a secondary superconducting order parameter, and the existence of gaps in spin and charge excitations.

Authors:

Kim, Duk Y. ^[1]; Lin, Shi -Zeng ^[1]; Weickert, Franziska ^[1]; Bauer, Eric D. ^[1]; Ronning, Filip ^[1]; Thompson, J. D. ^[1]; Movshovich, Roman ^[1]

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+ Show Author Affiliations

1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Publication Date:

Fri May 12 00:00:00 EDT 2017

Research Org.:

Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1374324

Alternate Identifier(s):

OSTI ID: 1356873

Report Number(s):

LA-UR-16-29172
Journal ID: ISSN 0031-9007; PRLTAO; TRN: US1702783

Grant/Contract Number:  

AC52-06NA25396

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review Letters

Additional Journal Information:

Journal Volume: 118; Journal Issue: 19; Journal ID: ISSN 0031-9007

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; Material Science