Explanation of Temperature-Dependent Resistivity of Sm-Doped Cuprates by Electron–Phonon Scattering

Abstract

The resistivity of electron-doped cuprate Sm1.85Ce0.15CuO4 − δ is theoretically analyzed within the framework of electron–phonon i.e., Bloch–Gruneisen (BG) model of resistivity. Characteristic temperatures as the Debye temperature and the Einstein temperature were first derived from an overlap repulsive potential. The optical phonons of the oxygen-breathing mode yield a relatively larger contribution to the resistivity compared to the contribution of acoustic phonons above 220 K. While to that, below this temperature, acoustic phonon is a major cause of resistivity. Estimated contribution to resistivity by considering both phonons i.e., ωac (acoustic phonons) and ωop (optical phonons), along with the zero limited resistivity, when subtracted from single crystal data, infers a quadratic temperature dependence over most of the temperature range (25 ≤ T ≤ 300). Power temperature dependence of ρdiff.{=[ρexp. – (ρ0 + ρe-ph(=ρac + ρop))]} points the contribution of electron–electron inelastic scattering. The present analysis allows us to infer that the single crystal experimental data is well approximated within the framework of BG electron–phonon model of resistivity. Further calculations of superconducting transition temperature and isotope effect exponent from Kresin's strong coupling theory indicates that the electron–phonon interaction plays an important role in the attractive pairing mechanism.