Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Ave., Argonne, Illinois 60439, USA.
Nanoscale. 2019 Nov 28;11(46):22351-22358. doi: 10.1039/c9nr07857f.
Charge density waves and negative differential resistance are seemingly unconnected physical phenomena. The former is an ordered quantum fluid of electrons, intensely investigated for its relation with superconductivity, while the latter receives much attention for its potential applications in electronics. Here we show that these two phenomena can not only coexist but also that the localized electronic states of the charge density wave are essential to induce negative differential resistance in a transition metal dichalcogenide, 1T-TaS2. Using scanning tunneling microscopy and spectroscopy, we report the observation of negative differential resistance in the commensurate charge density wave state of 1T-TaS2. The observed phenomenon is explained by the interplay of interlayer and intra-layer tunneling with the participation of the atomically localized states of the charge density wave maxima and minima. We demonstrate that lattice defects can locally affect the coupling between the layers and are therefore a mechanism to realize NDR in these materials.
电荷密度波和负微分电阻似乎是两个毫不相干的物理现象。前者是电子的有序量子流体，因其与超导性的关系而受到深入研究；而后者则因其在电子学中的潜在应用而备受关注。在这里，我们表明这两种现象不仅可以共存，而且电荷密度波的局域电子态对于在过渡金属二卤化物 1T-TaS2 中诱导负微分电阻是必不可少的。我们使用扫描隧道显微镜和光谱学报告了在 1T-TaS2 的准电荷密度波态中观察到的负微分电阻。观察到的现象可以通过层间和层内隧道的相互作用以及电荷密度波极大值和极小值的原子局域态的参与来解释。我们证明晶格缺陷可以局部影响层间的耦合，因此是在这些材料中实现 NDR 的一种机制。
