  The change in the electronic structure of layered Cu$_{x}$IrTe$_{2}$ has been
characterized by transport and spectroscopic measurements, combined with
first-principles calculations. The Cu-intercalation suppresses the monoclinic
distortion, giving rise to the stabilization of the trigonal phase with
superconductivity. Thermopower and Hall resistivity measurements suggest the
multiband nature with hole and electron carriers for this system, which is
masked by the predominance of the hole carriers enhanced by the interlayer
hybridization in the trigonal phase. Rather than the instability of Ir $d$
band, a subtle balance between the interlayer and intralayer Te-Te
hybridizations is proposed as a main factor dominating the structural
transition and the superconductivity.
