A new heavy-fermion superconductor CeIrIn ₅ : A relative of the cuprates?

Abstract

CeIrIn5 is a member of a new family of heavy-fermion compounds and has a\nSommerfeld specific heat coefficient of 720 mJ/mol-K2. It exhibits a bulk,\nthermodynamic transition to a superconducting state at Tc=0.40 K, below which\nthe specific heat decreases as T2 to a small residual T-linear value.\nSurprisingly, the electrical resistivity drops below instrumental resolution at\na much higher temperature T0=1.2 K. These behaviors are highly reproducible and\nfield-dependent studies indicate that T0 and Tc arise from the same underlying\nelectronic structure. The layered crystal structure of CeIrIn5 suggests a\npossible analogy to the cuprates in which spin/charge pair correlations develop\nwell above Tc.\n