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arXiv 1405.3152cond-mat.mtrl-sci
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FeGa3中的声子拖曳效应

Phonon-drag effect in FeGa3

Maik Wagner-Reetz, Deepa Kasinathan, Walter Schnelle, Raul Cardoso-Gil, Helge Rosner, Yuri Grin, Peter Gille

摘要:

系统地研究了单晶和多晶FeGa 3在宽温度范围内的热电性能。在20 K以下的低温下,在单晶样品中发现了先前未知的热导率(400-800 W·K^-1·m-1)的显著峰值和相应的热电势最大值(约为-16000 microV/K)。在单晶中沿[100]和[001]方向的测量表明,在电和热输运中只有轻微的各向异性。从磁化率和热容测量,结构或磁性相变被排除在外。使用基于密度泛函理论的计算,我们重新审视了FeGa 3的电子结构,并比较了磁性(包括相关性)和非磁性电子态密度。采用半经典玻尔兹曼输运理论计算了固定载流子浓度下的热电势,计算结果与实验数据相当吻合,排除了强电子关联作为低温增强解释的可能性。最后,经过仔细的审查,我们分配的峰的热电势的声子拖曳效应,这是支持热电势测量在磁场的表现。

英文摘要:

The thermoelectric properties of single- and polycrystalline FeGa3 are systematically investigated over a wide temperature range. At low temperatures, below 20 K, previously not known pronounced peaks in the thermal conductivity (400-800 W K^-1m-1) with corresponding maxima in the thermopower (in the order of -16000 microV/K) were found in single crystalline samples. Measurements in single crystals along [100] and [001] directions indicate only a slight anisotropy in both the electrical and thermal transport. From susceptibility and heat capacity measurements, a structural or magnetic phase transition was excluded. Using density functional theory-based calculations, we have revisited the electronic structure of FeGa3 and compared the magnetic (including correlations) and non-magnetic electronic density of states. Thermopower at fixed carrier concentrations are calculated using semi-classical Boltzmann transport theory, and the calculated results match fairly with our experimental data and exclude the possibility of strong electronic correlations as an explanation for the low temperature enhancement. Eventually, after a careful review, we assign the peaks in the thermopower as a manifestation of the phonon-drag effect, which is supported by thermopower measurements in a magnetic field.

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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