Normal-state conductivity of underdoped to overdoped cuprate superconductors: Pseudogap effects on the in-plane and c-axis charge transports

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• 作者：S. Dzhumanov ; ^{dzhumanov@inp.uz" class="auth_mail} ; O.K. Ganiev ; Sh.S. Djumanov
• 关键词：High-Tc cuprates ; Polarons ; Polaronic Cooper pairs ; Bipolarons ; Pairing pseudogaps ; Transport properties
• 刊名：Physica B
• 出版年：1 May, 2014
• 年：2014
• 卷：440
• 期：Complete
• 页码：17-32
• 全文大小：933 K

文摘

We have developed a theory of the unusual in-plane and c-axis charge transports in hole-doped cuprate superconductors and explain the temperature- and doping-dependent in-plane resistivity 蟻_ab, c-axis resistivity 蟻_c and resistivity anisotropy seen experimentally above T_c. We argue that the relevant current carriers in these materials above T_c are hole-like. The in-plane conductivity of underdoped to overdoped cuprates is considered as the conductivity of hole polarons and preformed Cooper pairs at their scattering by lattice vibrations in hole-rich CuO₂ layers (with nonzero thickness). The appropriate Boltzmann transport equations were used to calculate the conductivity of polaronic carriers and bosonic Cooper pairs above and below the pseudogap (PG) temperature T^{鈦?/sup> in the relaxation time approximation. We show that the linearity of 蟻_ab(T) above T鈦?/sup> is associated with the polaron-phonon scattering, while different deviations from the T-linear behavior in 蟻_ab(T) below T鈦?/sup> are caused by transition to the BCS-like PG regime. The specific model for layered cuprates is used to simulate the c-axis transport and to calculate the c-axis conductivity associated with the thermal dissociation of localized bipolarons in carrier-poor regions between the CuO₂ layers into hole polarons which subsequently move by hopping along the c-axis. It is shown that the bipolaronic PG and carrier-confinement together cause the insulating 蟻_c(T) behavior in the cuprates. The calculated results for 蟻_ab(T), 蟻_c(T) and were compared with the experimental data obtained for various hole-doped cuprates. For all the considered cases, a good quantitative agreement was found between theory and experimental data.}