Inelastic electron tunneling spectroscopy by STM of phonons at solid surfaces and interfaces

Emi Minamitani, Noriaki Takagi, Ryuichi Arafune, Thomas Frederiksen, Tadahiro Komeda, Hiromu Ueba, Satoshi Watanabe

    Research output: Contribution to journalReview articlepeer-review

    2 Citations (Scopus)

    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.

    Original languageEnglish
    Pages (from-to)131-145
    Number of pages15
    JournalProgress in Surface Science
    Volume93
    Issue number4
    DOIs
    Publication statusPublished - 2018 Dec

    ASJC Scopus subject areas

    • Chemistry(all)
    • Condensed Matter Physics
    • Surfaces and Interfaces
    • Surfaces, Coatings and Films

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