Universality of the Mott–Ioffe–Regel limit in metals

摘要: The absence of resistivity saturation in many strongly correlated metals, including the high-temperature superconductors, is critically examined from viewpoint optical conductivity measurements. Coherent quasiparticle conductivity, form a Drude peak centred at zero frequency, found to disappear as mean free path (at ω = 0) becomes comparable with interatomic spacing. This basic loss coherence so-called Mott–Ioffe–Regel (MIR) limit suggests that universality MIR criterion preserved even presence strong electron correlations. We argue shedding spectral weight low frequencies, induced by correlation effects, primary origin extended positive slope high temperatures observed all ‘bad metals’. Moreover, common those metals which exhibit temperatures, scattering rate itself, extracted spectra, saturates value consisten...