AUTHOR=Maier Philipp , Hourigan Noah. J. , Ruckhofer Adrian , Bremholm Martin , Tamtögl Anton 

TITLE=Surface properties of 1T-TaS2 and contrasting its electron-phonon coupling with TlBiTe2 from helium atom scattering

JOURNAL=Frontiers in Chemistry

VOLUME=11

YEAR=2023

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2023.1249290

DOI=10.3389/fchem.2023.1249290

ISSN=2296-2646

ABSTRACT=<p>We present a detailed helium atom scattering study of the charge-density wave (CDW) system and transition metal dichalcogenide 1T-TaS<sub>2</sub>. In terms of energy dissipation, we determine the electron-phonon (e-ph) coupling, a quantity that is at the heart of conventional superconductivity and may even “drive” phase transitions such as CDWs. The e-ph coupling of TaS<sub>2</sub> in the commensurate CDW phase (<italic>λ</italic> = 0.59 ± 0.12) is compared with measurements of the topo-logical insulator TlBiTe<sub>2</sub> (<italic>λ</italic> = 0.09 ± 0.01). Furthermore, by means of elastic He diffraction and resonance/interference effects in He scattering, the thermal expansion of the surface lattice, the surface step height, and the three-dimensional atom-surface interaction potential are determined including the electronic corrugation of 1T-TaS<sub>2</sub>. The linear thermal expansion coefficient is similar to that of other transition-metal dichalcogenides. The He−TaS<sub>2</sub> interaction is best described by a corrugated Morse potential with a relatively large well depth and supports a large number of bound states, comparable to the surface of Bi<sub>2</sub>Se<sub>3</sub>, and the surface electronic corrugation of 1T-TaS<sub>2</sub> is similar to the ones found for semimetal surfaces.</p>