  We observe superconductivity below a critical temperature TC = 1.8 K in
single-crystal Ir3Te8, which also exhibits normal-state diamagnetism and a
linear temperature dependence of electrical resistivity for a wide temperature
interval, 20 K < T < 700 K. Single-crystal Ir3Te8 also undergoes a structural
phase transition at TS = 350 K from a cubic (above TS) to a rhombohedral
lattice below TS. Our first-principles electronic structure calculations reveal
two bands crossing the Fermi level; despite the three-dimensional lattice, one
band is quasi-two-dimensional, and is responsible for the observed diamagnetism
and structure transition. The strong non-Fermi-liquid behavior characterized by
the observed linearity in resistivity in such a nonmagnetic state suggests
novel physics in this newly discovered superconductor.
