Inelastic electron tunneling spectroscopy by STM of phonons at solid surfaces and interfaces. Issue 4 (December 2018)

• Record Type: Journal Article
• Authors: Minamitani, Emi; Takagi, Noriaki; Arafune, Ryuichi; Frederiksen, Thomas; Komeda, Tadahiro; Ueba, Hiromu; Watanabe, Satoshi
• Is Part Of: Progress in surface science. Volume 93:Issue 4(2018)
• Page Start: 131
• Page End: 145
• Publication Date: 2018-12
• Subjects: STM scanning tunneling spectroscopy -- IETS inelastic tunneling spectroscopy -- HAS helium atom scattering -- HREELS high-resolution electron energy loss spectroscopy -- ILPES inelastic laser photoemission spectroscopy -- EPC electron-phonon coupling -- DFT density functional theory -- DFPT density functional perturbation theory -- NEGF nonequilibrium Green's function; Surface chemistry -- Periodicals; Surfaces (Technology) -- Periodicals; Surface Properties -- Periodicals; Chimie des surfaces -- Périodiques; Surfaces (Technologie) -- Périodiques; 541.33
• DOI: 10.1016/j.progsurf.2018.09.002
• Languages: English
• ISSNs: 0079-6816

Abstract

Abstract: Inelastic electron tunneling spectroscopy (IETS) combined with scanning tunneling microscopy (STM) allows the acquisition of vibrational signals at surfaces. In STM-IETS, a tunneling electron may excite a vibration, and opens an inelastic channel in parallel with the elastic one, giving rise to a change in conductivity of the STM junction. Until recently, the application of STM-IETS was limited to the localized vibrations of single atoms and molecules adsorbed on surfaces. The theory of the STM-IETS spectrum in such cases has been established. For the collective lattice dynamics, i.e., phonons, however, features of STM-IETS spectrum have not been understood well, though in principle STM-IETS should also be capable of detecting phonons. In this review, we present STM-IETS investigations for surface and interface phonons and provide a theoretical analysis. We take surface phonons on Cu(1 1 0) and interfacial phonons relevant to graphene on SiC substrate as illustrative examples. In the former, we provide a theoretical formalism about the inelastic phonon excitations by tunneling electrons based on the nonequilibrium Green's function (NEGF) technique applied to a model Hamiltonian constructed in momentum space for both electrons and phonons. In the latter case, we discuss the experimentally observed spatial dependence of the STM-IETS spectrum and link it to local excitations of interfacial phonons based on ab-initio STM-IETS simulation.