Vortexlike excitations in the heavy-fermion superconductor<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>CeIrIn</mml:mi><mml:mn>5</mml:mn></mml:msub></mml:math>

We report a systematic study of temperature- and field-dependent charge $(\mathbf{\ensuremath{\rho}})$ and entropy $(\mathbf{S})$ transport in the heavy-fermion superconductor ${\mathrm{CeIrIn}}_{5}$. Its large positive thermopower ${S}_{xx}$ is typical of Ce-based Kondo lattice systems, and strong electronic correlations play an important role in enhancing the Nernst signal ${S}_{xy}$. By separating the off-diagonal Peltier coefficient ${\ensuremath{\alpha}}_{xy}$ from ${S}_{xy}$, we find that ${\ensuremath{\alpha}}_{xy}$ becomes positive and greatly enhanced at temperatures well above the bulk ${T}_{c}$. Compared with the nonmagnetic analog ${\mathrm{LaIrIn}}_{5}$, these results suggest vortexlike excitations in a precursor state to unconventional superconductivity in ${\mathrm{CeIrIn}}_{5}$. This study sheds light on the similarity of heavy-fermion and cuprate superconductors and on the possibility of states not characterized by the amplitude of an order parameter.

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