论文标题
2H-NBS2中的杂质小匹配电荷密度波和局部声子激发
Impurity-pinned incommensurate charge density wave and local phonon excitations in 2H-NbS2
论文作者
论文摘要
在这里，我们报告了2H-NBS2的超导状态的扫描隧道显微镜（STM）和光谱研究（STS）研究。我们直接可以看到由原子杂质钉住的不相称的电荷密度波（CDW）的存在。在强大的隧道条件下，STM尖端的电场从杂质中脱离了不增压的CDW。我们执行基于STM的非弹性隧道光谱（IET）来检测2H-NBS2中的声子激发，并测量原子杂质对局部声子激发的影响。与2H-NBS2中状态的计算振动密度相比，我们发现了与NB离子和S离子振动相对应的两个声子激发的分支，局部声子激发的强度对原子杂质不敏感。我们的结果表明，在2H-NBS2中，不稳定的CDW和超导性的共存，并打开了与基于STM的IET的过渡金属二进制基因生成元中检测原子尺度的声子激发的方式。
Here we report a scanning tunneling microscopy (STM) and spectroscopy (STS) study in the superconducting state of 2H-NbS2. We directly visualize the existence of incommensurate charge density wave (CDW) that is pinned by atomic impurities. In strong tunneling conditions, the incommensurate CDW is de-pinned from impurities by the electric field from STM tip. We perform STM-based inelastic tunneling spectroscopy (IETS) to detect phonon excitations in 2H-NbS2 and measure the influence of atomic impurities on local phonon excitations. In comparison with the calculated vibrational density of states in 2H-NbS2, we find two branches of phonon excitations which correspond to the vibrations of Nb ions and S ions, and the strength of the local phonon excitations is insensitive to the atomic impurities. Our results demonstrate the coexistence of incommensurate CDW and superconductivity in 2H-NbS2, and open the way of detecting atomic-scale phonon excitations in transition metal dichalcogenides with STM-based IETS.
