Universality of the Mott-Ioffe-Regel limit in metals
Universality of the Mott-Ioffe-Regel limit in metals
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DOI：
10.1080/14786430410001716944
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发表时间：
2004-09-21
影响因子：
1.6
通讯作者：
Takagi, H
中科院分区：
文献类型：
--
作者：
Hussey, NE;Takenaka, K;Takagi, H
本文从光学电导率测量的角度出发，对许多强关联金属（包括高温超导体）中电阻率饱和的不存在进行了严格的研究。相干准粒子电导率，在以零频率为中心的德鲁德峰的形式，被发现消失的平均自由程（在ω = 0）变得可比的原子间的间距。在所谓的Mott-Ioffe-Regel（MIR）极限下，这种基本的相干性损失表明，即使在存在强电子相关的情况下，MIR准则的普适性也得到了保留。我们认为，脱落的频谱重量在低频率下，诱导强相关效应，是延长的电阻率的正斜率的高温观察到的所有所谓的“坏金属”的主要来源。此外，与那些在高温下表现出电阻率饱和的金属一样，从光谱中提取的散射率本身在与MIR极限一致的值处饱和。我们认为可能的影响，这个天花板的散射率可能有我们的理解运输内的各种各样的坏金属，并建议一个更好的方法来分析其光学响应。
The absence of resistivity saturation in many strongly correlated metals, including the high-temperature superconductors, is critically examined from the viewpoint of optical conductivity measurements. Coherent quasiparticle conductivity, in the form of a Drude peak centred at zero frequency, is found to disappear as the mean free path (at omega = 0) becomes comparable with the interatomic spacing. This basic loss of coherence at the so-called Mott-Ioffe-Regel (MIR) limit suggests that the universality of the MIR criterion is preserved even in the presence of strong electron correlations. We argue that the shedding of spectral weight at low frequencies, induced by strong correlation effects, is the primary origin of the extended positive slope of the resistivity to high temperatures observed in all so-called 'bad metals'. Moreover, in common with those metals which exhibit resistivity saturation at high temperatures, the scattering rate itself, as extracted from optical spectra, saturates at a value consistent with the MIR limit. We consider possible implications that this ceiling in the scattering rate may have for our understanding of transport within a wide variety of bad metals and suggest a better method for analysing their optical response.