论文标题
nbs $ \ boldsymbol {_2} $的2H和3R多型中的费米和电子耦合
Fermiology and electron-phonon coupling in the 2H and 3R polytypes of NbS$\boldsymbol{_2}$
论文作者
论文摘要
我们研究了NBS $ _2 $的2H和3R多型的电子结构。通过角度分辨光发射光谱测量的费米表面在大小上有显着差异，这反映了3R-NB $ _ {1+x} $ s $ _2 $在3R-NB $ _2 $ _2 $中显着增加的带填充，而与2H-NBS $ _2 $相比，我们将其归因于其他固定nb的额外的内在NB，这是由电子供电的其他供电。因此，我们发现化学计量法而不是堆叠排列是两个阶段电子和物理特性差异的最重要因素。我们对2H相的高分辨率数据显示了光谱函数中的扭结，这些扭结是电子音波耦合的指纹。但是，对于带有NB 4 $ d_ {x^2-y^2，xy} $字符的频段的各个部分而言，耦合的强度比NB 4 $ d_ {3z^2-r^2} $要大得多。我们的结果提供了一个实验框架，用于解释2H-NBS $ _2 $中的两间隙超导性和“潜在”电荷密度波。
We investigate the electronic structure of the 2H and 3R polytypes of NbS$_2$. The Fermi surfaces measured by angle-resolved photoemission spectroscopy show a remarkable difference in size, reflecting a significantly increased band filling in 3R-Nb$_{1+x}$S$_2$ compared to 2H-NbS$_2$, which we attribute to the presence of additional interstitial Nb which act as electron donors. Thus we find that the stoichiometry, rather than the stacking arrangement, is the most important factor in the difference in electronic and physical properties of the two phases. Our high resolution data on the 2H phase shows kinks in the spectral function that are fingerprints of the electron-phonon coupling. However, the strength of the coupling is found to be much larger for the the sections of bands with Nb 4$d_{x^2-y^2,xy}$ character than for the Nb 4$d_{3z^2-r^2}$. Our results provide an experimental framework for interpreting the two-gap superconductivity and "latent" charge density wave in 2H-NbS$_2$.
