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arXiv 1806.04094cond-mat.str-el
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$T$ -平方电阻率前置因子失配导致WP $_2$偏离Wiedemann-Franz定律

Departure from the Wiedemann-Franz Law in WP$_2$ Driven by Mismatch in $T$-square Resistivity Prefactors

Alexandre Jaoui, Benoît Fauqué, Carl Willem Rischau, Alaska Subedi, Chenguang Fu, Johannes Gooth, Nitesh Kumar, Vicky Süß, Dmitrii L. Maslov, Claudia Felser, Kamran Behnia

摘要:

Wiedemann-Franz(WF)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,它的有效性程度是一个在不同背景下提出的问题。我们报告的电,$σ$,和热,$κ$,在WP $_2$单晶的电导率的研究。WF保持在2K,但在变暖时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。我们发现,这是由一个五倍的差异之间的$T$ -平方前置因子的电和热的介电常数,电子-电子散射所造成的。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。

英文摘要:

The Wiedemann-Franz (WF) law establishes a link between heat and charge transport due to electrons in solids. The extent of its validity in presence of inelastic scattering is a question raised in different contexts. We report on a study of the electrical, $σ$, and thermal, $κ$, conductivities in WP$_2$ single crystals. The WF holds at 2 K, but a downward deviation rapidly emerges upon warming. At 13 K, there is an exceptionally large mismatch between 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.

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