Charge-orbital density wave and superconductivity in the strong spin-orbit coupled IrTe ₂ Pd

Using transmission electron microscopy, the anomalies in resistivity and magnetic susceptibility at ∼262K in IrTe ₂ are found to accompany the superlattice peaks with q=(1/5,0,-1/5). The wave vector is consistent with our theoretical calculation for the Fermi surface nesting vector, indicating that the ∼262K transition is of the charge-orbital density wave (DW) type. We also discovered that both Pd intercalation and substitution induce bulk superconductivity with T _c up to ∼3K, which competes with DW in a quantum critical pointlike manner.