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

DOI: 10.1103/PhysRevB.103.155105 DOI Help

Authors: Zakariae El Youbi (Diamond Light Source; CY Cergy-Paris Université) , Sung Won Jung (Diamond Light Source) , Christine Richter (CY Cergy Paris Université; Université Paris-Saclay, CEA, CNRS) , Karol Hricovini (CY Cergy-Paris Université; Université Paris-Saclay, CEA, CNRS) , Cephise Cacho (Diamond Light Source) , Matthew D. Watson (Diamond Light Source)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Review B , VOL 103

State: Published (Approved)
Published: April 2021
Diamond Proposal Number(s): 26443

Open Access Open Access

Abstract: We investigate the electronic structure of the 2 H and 3 R polytypes of Nb S 2 . The Fermi surfaces measured by angle-resolved photoemission spectroscopy show a remarkable difference in size, reflecting a significantly increased band filling in 3 R − Nb 1 + x S 2 compared to 2 H − Nb S 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 2 H 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 , x y character than for the Nb 4 d 3 z 2 − r 2 . Our results provide an experimental framework for interpreting the two-gap superconductivity and latent charge density wave in 2 H − Nb S 2 .

Journal Keywords: Charge density waves; Electron-phonon coupling; Transition-metal dichalcogenide; Angle-resolved photoemission spectroscopy

Subject Areas: Physics, Materials

Instruments: I05-ARPES

Added On: 06/04/2021 11:24


Discipline Tags:

Materials Science Quantum Materials Superconductors Physics

Technical Tags:

Spectroscopy Angle Resolved Photoemission Spectroscopy (ARPES)