Explanation of the temperature dependence of resistivity in high-Tc superconducting Ba0.6K0.4BiO3 by electron-phonon scattering

Superconductivity and normal state resistivity of Ba0.6K0.4BiO3: an optical phonon approach

“…It is argued that the dependence change from ρ(T ) ∝ T 2 at low temperature to ρ(T ) ∝ T at high temperatures as observed in electron doped cuprates [23] which is related to a 3D to 2D crossover is not true for BKBO systems which with its cubic structure and electron system is unlikely to change dimensionality. From the present analysis of normal-state resistivity in BKBO systems we support the argument made by Golovashkin et al [12]. The 3D to 2D crossover concept, although applicable to anisotropic cuprates because of their low dimensionality, does not hold for 3D isotropic cubic BKBO superconductors.…”

“…While determining the longitudinal optical phonon frequency, we have made an approximation that the vibrational frequencies are independent of wavevector (q), and used the nearest-neighbour ionic potential. Furthermore, Golovashkin et al [12] have predicted a crossover from T 2 to T characteristic for the normalstate resistivity. It is argued that the dependence change from ρ(T ) ∝ T 2 at low temperature to ρ(T ) ∝ T at high temperatures as observed in electron doped cuprates [23] which is related to a 3D to 2D crossover is not true for BKBO systems which with its cubic structure and electron system is unlikely to change dimensionality.…”

“…The temperature dependence of the resistivity (ρ) has been analysed by Golovashkin et al [12] and they found that ρ(T ) is quadratic with respect to temperature (T < 180 K) and rises linearly with temperature when T > 200 K. The existence of ρ(T ) ∝ T 2 over a wide temperature range 30 ≤ T ≤ 200 K was previously interpreted in terms of electron-electron scattering for Nd 1.85 Ce 0.15 CuO 4 , superconductors [23]. In interpreting the resistivity data, Golovashkin et al [12] used the values for the Debye and Einstein temperatures determined from the phonon density of states using neutron scattering data.…”

“…In interpreting the resistivity data, Golovashkin et al [12] used the values for the Debye and Einstein temperatures determined from the phonon density of states using neutron scattering data. On the other hand, in the present calculations, we have used the coupling strength for optical phonons as deduced from the density of states at the Fermi level and the McMillan-Hopfield parameter.…”

“…Recently, the resistivity of single crystals of cubic Ba 0.6 K 0.4 BiO 3 with T c = 30 K has been reported in the temperature range 4.2-300 K [12]. The temperature dependence of the resistivity of a single crystal displays a metal-like behaviour.…”