Low temperature specific heat and thermal conductivity measurements on the ambient pressure heavy fermion superconductors and reveal power law temperature dependences of these quantities below . The low temperature specific heat in both and includes terms, consistent with the presence of nodes in the superconducting energy gap. The thermal conductivity data present a -linear term consistent with the universal limit , and a low temperature variation in the clean limit , also in accord with prediction for an unconventional superconductor with lines of nodes.
- Received 15 November 2000
- Revised 23 February 2001
- Published in the issue dated 28 May 2001
© 2001 The American Physical Society