Departure from the Wiedemann-Franz law in WP2 driven by mismatch in T-square resistivity prefactors
Departure from the Wiedemann-Franz law in WP2 driven by mismatch in T-square resistivity prefactors
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DOI：
10.1038/s41535-018-0136-x
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发表时间：
2018-12-10
影响因子：
5.7
通讯作者：
Behnia, Kamran
中科院分区：
文献类型：
--
作者：
Jaoui, Alexandre;Fauque, Benoit;Behnia, Kamran
Wiedemann-Franz定律建立了热量和固体中电子引起的电荷传输之间的联系。在非弹性散射的存在下，其有效性的程度是一个在不同背景下提出的问题。在这里，我们报告的电，西格玛，和热，卡帕，在WP 2单晶的电导率的研究。Wiedemann-Franz定律在2 K时成立，但在变暖时会迅速出现向下的偏差。在13 K时，Lorenz数和Sommerfeld值之间存在异常大的失配。我们表明，这是由一个五倍的差异T-平方前置因子的电和热的介电常数，都引起的电子-电子散射。这意味着由于强屏蔽，电子之间存在大量的小散射角碰撞。通过量化的相对频率的碰撞守恒的动量通量，但降解热通量，我们确定了一个狭窄的温度窗口，其中的层次结构的散射时间可能对应于流体动力学制度。
The Wiedemann-Franz law establishes a link between heat and charge transport due to electrons in solids. The extent of its validity in the presence of inelastic scattering is a question raised in different contexts. Here we report on a study of the electrical, sigma, and thermal, kappa, conductivities in WP2 single crystals. The Wiedemann-Franz law holds at 2 K, but a downward deviation rapidly emerges upon warming. At 13 K, there is an exceptionally large mismatch between the Lorenz number and the Sommerfeld value. We show that this is driven by a fivefold discrepancy between the T-square prefactors of electrical and thermal resistivities, both caused by electron-electron scattering. This implies the existence of abundant small-scattering-angle collisions between electrons, due to strong screening. By quantifying the relative frequency of collisions conserving momentum flux, but degrading heat flux, we identify a narrow temperature window where the hierarchy of scattering times may correspond to the hydrodynamic regime.