Observation of superconductivity and anomalous electrical resistivity in single-crystal Ir₃Te₈

We observe an unusual combination of normal and superconducting state properties without any signature of strong spin fluctuations in single-crystal Ir₃Te₈. The electrical resistivity does not saturate by 700 K but exhibits a low-resistivity ratio, and it exhibits two extended linear regimes (approximately 20-330 and 370-700 K) with the same slope, separated by a small hysteretic interval marking a strong first-order phase transition from cubic to rhombohedral lattice symmetry at T_S = 350 K. The electronic heat-capacity coefficient (11mJmol^-1K^-2) is consistent with a net diamagnetic, rather than a Pauli paramagnetic, normal state that yields to superconductivity below a critical temperature T_C = 1.8 K. The size of the heat-capacity jump near T_C indicates bulk superconductivity.