Imaging phonon-mediated hydrodynamic flow in WTe2
Imaging phonon-mediated hydrodynamic flow in WTe2
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DOI：
10.1038/s41567-021-01341-w
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发表时间：
2021-09-16
期刊：
影响因子：
19.6
通讯作者：
Yacoby, Amir
中科院分区：
文献类型：
--
作者：
Vool, Uri;Hamo, Assaf;Yacoby, Amir
在相互作用的存在下，凝聚态系统中的电子可以表现出流体动力学的行为，表现出与经典流体相关的现象，如漩涡和泊泽维尔流（1-3）。在大多数导体中，电子-电子相互作用通过筛选效应最小化，阻碍了对流体动力材料的寻找；然而，最近，一类半金属已被报道显示出突出的相互作用（4,5）。本文利用金刚石中的氮空位缺陷对局部磁场进行成像，研究了层状半金属二碲化钨中的电流流动。我们对三维二碲化钨内部的空间电流分布进行了成像，发现它具有不均匀的电流密度，表明流体动力流动。我们的温度分辨电流剖面测量揭示了非单调的温度依赖性，在大约20 K时具有最强的水动力效应。我们还报告从头计算表明，电子-电子相互作用不能由库仑相互作用单独解释，而是主要由声子介导。这为寻找高载流子密度材料中的流体动力学流动和突出的电子相互作用提供了一条有前途的途径。
In the presence of interactions, electrons in condensed-matter systems can behave hydrodynamically, exhibiting phenomena associated with classical fluids, such as vortices and Poiseuille flow(1-3). In most conductors, electron-electron interactions are minimized by screening effects, hindering the search for hydrodynamic materials; however, recently, a class of semimetals has been reported to exhibit prominent interactions(4,5). Here we study the current flow in the layered semimetal tungsten ditelluride by imaging the local magnetic field using a nitrogen-vacancy defect in a diamond. We image the spatial current profile within three-dimensional tungsten ditelluride and find that it exhibits non-uniform current density, indicating hydrodynamic flow. Our temperature-resolved current profile measurements reveal a non-monotonic temperature dependence, with the strongest hydrodynamic effects at approximately 20 K. We also report ab initio calculations showing that electron-electron interactions are not explained by the Coulomb interaction alone, but are predominantly mediated by phonons. This provides a promising avenue in the search for hydrodynamic flow and prominent electron interactions in high-carrier-density materials.