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arXiv 2602.21110cond-mat.mtrl-scicond-mat.dis-nncond-mat.other
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R$_3$Co$_4$Ge$_{13}$ (R = Y, Lu)单晶中电导率温度依赖性的异常

Anomalous temperature dependence of the electrical resistivity in R$_3$Co$_4$Ge$_{13}$ (R = Y, Lu) single crystals

Centro de Ciências Naturais e Humanas (CCNH), Universidade Federal do ABC(自然与人文科学中心(CCNH),ABC联邦大学)

Juliana Gonçalves Dias, Shyam Sundar, Leticie Mendonça-Ferreira, Marcos A. Avila

AI总结:

研究了R$_3$Co$_4$Ge$_{13}$单晶中电导率的异常温度依赖性,发现其行为不同于传统模型,归因于结构无序和低载流子密度。

摘要:

强无序的存在可以显著影响金属系统中的电导。在这里,我们研究了非磁性单晶Remeika相笼化合物R$_3$Co$_4$Ge$_{13}$ (R = Y, Lu)的电导率温度依赖性,$ρ(T)$。与文献中密度态(DOS)计算不同,两种化合物实验测得的$ρ(T)$表现出半导体样行为,我们将其归因于其独特的晶体结构和低载流子密度导致的强结构无序。对电导率数据的详细分析表明,无论是阿伦尼乌斯热激活定律还是变程跃迁(VRH)模型都无法在2-350 K的宽温度范围内充分描述其温度依赖性。然而,一个结合通过半导体和金属通道并行传导的模型提供了充分的解释。除了在$\sim 10$ K以下占主导地位的金属传导外,两种样品均显示出电导率的负温度系数($dρ/dT$)。在没有磁性杂质的情况下,观察到的$dρ/dT < 0$被解释为结构Kondo机制。

英文摘要:

The presence of strong disorder can significantly impact electrical conduction in metallic systems. Here, we investigate the temperature dependence of the electrical resistivity, $ρ(T)$, in nonmagnetic single crystals of the Remeika-phase cage compounds R$_3$Co$_4$Ge$_{13}$ (R = Y, Lu). Contrary to the density of states (DOS) calculations in the literature, the experimentally measured $ρ(T)$ in both compounds exhibits semiconducting-like behavior, which we attribute to the strong structural disorder due to its unique crystal structure and low carrier-density. A detailed analysis of the electrical resistivity data reveals that neither the Arrhenius thermal activation law nor variable-range hopping (VRH) models can adequately describe their temperature dependence over the broad temperature range of 2-350 K. However, a model incorporating parallel conduction through both semiconducting and metallic channels provides an adequate explanation. In addition to a dominant metallic conduction below $\sim 10$~K, a negative temperature coefficient of the electrical resistivity ($dρ/dT$) is found in both samples. In the absence of magnetic impurities, the observed $dρ/dT < 0$ is interpreted in terms of the structural Kondo mechanism.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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