Relation between the structural phase transition and superconductivity in CuxIrTe2−ySey

Abstract

We have investigated the relation between structural transition with Ir-dimer formation and superconductivity in IrTe2 by combining the Se substitution and the Cu intercalation. Regardless of the structural transition temperature (Ts), which increases with increasing the Se content (y) in IrTe2−ySey, superconductivity emerges robustly by the Cu intercalation. As the Cu content x in CuxIrTe2−ySey increases, Ts tends to decrease, followed by the emergence of superconductivity with showing the highest critical temperature (Tc) at the optimum Cu concentration (xopt) close to the structural phase boundary. Based on the transport and thermodynamic properties, the electron-phonon coupling constant is found to be enhanced near the structural phase boundary, which suggests an essential role of the structural instability for the superconductivity in doped IrTe2. With increasing y from 0 to 0.5 in CuxIrTe2−ySey, Ts at x=0 increases by about 80%, whereas Tc at x=xopt decreases by about 20%. This can be understood by the weakening of the interlayer hybridization upon the Se substitution, resulting in the weak but negative correlation between Ts and Tc through y.

Source-reported materials — not catalogue approval

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