Origin of the Electron–Phonon Interaction of Topological Semimetal Surfaces Measured with Helium Atom Scattering

Abstract

He atom scattering has been demonstrated to be a sensitive probe of the electron−phonon interaction parameter λ at metal and metal-overlayer surfaces. Here it is shown that the theory linking λ to the thermal attenuation of atom scattering spectra (the Debye−Waller factor) can be applied to topological semimetal surfaces, such as the quasi-onedimensional charge-density-wave system Bi(114) and the layered pnictogen chalcogenides. The electron−phonon coupling, as determined for several topological insulators belonging to the class of bismuth chalcogenides, suggests a dominant contribution of the surface quantum well states over the Dirac electrons in terms of λ.

Grazing incidence fast atom diffraction, similarities and differences with thermal energy atom scattering (TEAS)

“…This might not be the case on a surface where specific vibration modes exist 86 that are localized close to the surface. Using a slab approach of the surface, Schram and Heller 87 suggested that the initial excitation could indeed dilute in many phonon modes and that the apparent quasi-elastic diffraction could, in part, be due to the excitation of very low energy mode having a negligible contribution to the angular and energy straggling.…”

The electron–phonon coupling constant for single-layer graphene on metal substrates determined from He atom scattering

“…14,15 Since the thermal attenuation of any quantum peak feature in the atom scattering spectra is due to an average over the mean square displacement of all phonon modes weighted by the respective electron-phonon coupling, it is not surprising that such attenuation can be related to the average l HAS = hl Q,n i. [16][17][18][19] This will be discussed in more detail below in Section 2 where the theory is briefly outlined. In Section 3 values of l HAS are obtained from the available He atom scattering data on C(0001).…”

Atom-surface van der Waals potentials of topological insulators and semimetals from scattering measurements

“…tion regime[83][84][85] including modifications of the surface electronic structure via adsorption[86][87][88][89] and effects relevant for heterogeneous catalysis or sensing applications90,91 .4 | 1-15 J o u r n a l N a me , [ y e a r ] , [ v o l . ] ,…”