Low Temperature Specific Heat and Thermal Conductivity in Superconducting UTe2

The measurements [Phys. Rev. B 100, 220504(R) (2019)] do not detect noticeable thermal conductivity in superconducting UTe2 in the T = 0 limit. At the same time the same crystals exhibit a large residual density of states comparable with its normal state value. The improvement of samples quality leads to the augmentation of critical temperature of transition to the superconducting state accompanied by the decreasing of residual specific heat ratio C(T)=T at T ??? 0. There is presented an analytic derivation of this inverse correlation property in concrete cases of triplet superconducting states with node-less and point-nodes order parameters allowed by symmetry in UTe2. The obtained explicit formulas for the residual thermal conductivity are in reasonable correspondence with observations.

Automated summary

The measurements in superconducting UTe2 show that there is no noticeable thermal conductivity at T = 0, while the crystals exhibit a large residual density of states comparable to the normal state. Improving the quality of the samples leads to an increase in the critical temperature of the transition to superconducting state, accompanied by a decrease in the residual specific heat ratio at T ??? 0. An analytical derivation of the inverse correlation property in UTe2 is presented, specifically for triplet superconducting states with node-less and point-nodes order parameters allowed by symmetry. The obtained explicit formulas for the residual thermal conductivity are in reasonable agreement with observations.