Fermiology and electron-phonon coupling in the 2H and 3R polytypes of NbS2

• DOI: 10.1103/physrevb.103.155105
• Publication Date: 2021-04-02T16:37:51Z
• Authors: Zakariae El Youbi; Sung Won Jung; Christine Richter; Karol Hricovini; Cephise Cacho; Matthew D. Watson
• Keywords: 0103 physical sciences; 01 natural sciences

We investigate the electronic structure of 2H and 3R polytypes NbS$_2$. The Fermi surfaces measured by angle-resolved photoemission spectroscopy show a remarkable difference in size, reflecting significantly increased band filling 3R-Nb$_{1+x}$S$_2$ compared to 2H-NbS$_2$, which we attribute presence additional interstitial Nb act as electron donors. Thus find that stoichiometry, rather than stacking arrangement, is most important factor physical properties two phases. Our high resolution data on phase shows kinks spectral function are fingerprints electron-phonon coupling. However, strength coupling found be much larger for sections bands with 4$d_{x^2-y^2,xy}$ character 4$d_{3z^2-r^2}$. results provide an experimental framework interpreting two-gap superconductivity "latent" charge density wave 2H-NbS$_2$.