IBM Research-Zurich, Säumerstrasse 4, 8803, Rüschlikon, Switzerland.
Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187, Dresden, Germany.
Nat Commun. 2018 Oct 5;9(1):4093. doi: 10.1038/s41467-018-06688-y.
In stark contrast to ordinary metals, in materials in which electrons strongly interact with each other or with phonons, electron transport is thought to resemble the flow of viscous fluids. Despite their differences, it is predicted that transport in both conventional and correlated materials is fundamentally limited by the uncertainty principle applied to energy dissipation. Here we report the observation of experimental signatures of hydrodynamic electron flow in the Weyl semimetal tungsten diphosphide. Using thermal and magneto-electric transport experiments, we find indications of the transition from a conventional metallic state at higher temperatures to a hydrodynamic electron fluid below 20 K. The hydrodynamic regime is characterized by a viscosity-induced dependence of the electrical resistivity on the sample width and by a strong violation of the Wiedemann-Franz law. Following the uncertainty principle, both electrical and thermal transport are bound by the quantum indeterminacy, independent of the underlying transport regime.
与普通金属形成鲜明对比的是，在电子与彼此或声子强烈相互作用的材料中，电子输运被认为类似于粘性流体的流动。尽管存在差异，但据预测，传统和相关材料中的输运都受到应用于能量耗散的不确定性原理的基本限制。在这里，我们报告了在 Weyl 半金属二磷钨中观察到的流体动力学电子流的实验特征。通过热和磁电输运实验，我们发现了在较高温度下从传统金属态到 20 K 以下的流体动力学电子态的转变的迹象。流体动力学状态的特征是电导率对样品宽度的粘性依赖性，以及对维德曼-弗朗兹定律的强烈违反。根据不确定性原理，电输运和热输运都受到量子不确定性的限制，而与基础输运机制无关。
