Scanning tunneling spectroscopy

About: Scanning tunneling spectroscopy is a research topic. Over the lifetime, 7886 publications have been published within this topic receiving 213828 citations.

Influence of Domain Walls in the Incommensurate Charge Density Wave State of Cu Intercalated 1 T − TiSe 2

Abstract: We report a low-temperature scanning tunneling microscopy study of the charge density wave (CDW) order in 1T-TiSe_{2} and Cu_{0.08}TiSe_{2}. In pristine 1T-TiSe_{2} we observe a long-range coherent commensurate CDW (CCDW) order. In contrast, Cu_{0.08}TiSe_{2} displays an incommensurate CDW (ICDW) phase with localized CCDW domains separated by domain walls. Density of states measurements indicate that the domain walls host an extra population of fermions near the Fermi level which may play a role in the emergence of superconductivity in this system. Fourier transform scanning tunneling spectroscopy studies suggest that the dominant mechanism for CDW formation in the ICDW phase may be electron-phonon coupling.

Interplay between structural, chemical, and spectroscopic properties of Ag ∕ Au ( 111 ) epitaxial ultrathin films: A way to tune the Rashba coupling

Abstract: An overview of structural, chemical, and electronic properties of epitaxial $\mathrm{Ag}∕\mathrm{Au}(111)$ ultrathin films investigated by scanning tunneling microscopy and scanning tunneling spectroscopy and angle-resolved photoelectron spectroscopy is presented. New insights are exhibited: (i) a short-range ordered surface reconstruction is clearly observed for deposition at $300\phantom{\rule{0.3em}{0ex}}\mathrm{K}$; (ii) self-organized ordering of Ag islands is obtained at $T\ensuremath{\simeq}80\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. In this whole temperature range, the $\mathrm{Ag}∕\mathrm{Au}(111)$ interface is shown to be (nearly) abrupt. An annealing of the elaborated room temperature leads to a strong intermixing and favors the formation of a chemically disordered surface alloy. The Shockley state parameters have been fully characterized for both interfaces. Surprisingly, the Rashba parameter is shown to scale the binding energy of the surface state in both cases. A simple one-dimensional model, taking into account the exponential decrease of the surface state wave function, allows us a quantitative understanding of the evolution of the surface state parameters. Indeed, the strength of the spin-orbit splitting is shown to be proportional to the number of heavy atoms probed by the surface state wave function, revealing its atomic character. Therefore, the strength of the Rasba coupling is shown to be tuned by adjusting the number of Ag epitaxial layers or the $\mathrm{Ag}\text{\ensuremath{-}}\mathrm{Au}$ alloy composition.

Revealing the Electronic Structure of Silicon Intercalated Armchair Graphene Nanoribbons by Scanning Tunneling Spectroscopy

Abstract: The electronic properties of graphene nanoribbons grown on metal substrates are significantly masked by the ones of the supporting metal surface. Here, we introduce a novel approach to access the frontier states of armchair graphene nanoribbons (AGNRs). The in situ intercalation of Si at the AGNR/Au(111) interface through surface alloying suppresses the strong contribution of the Au(111) surface state and allows for an unambiguous determination of the frontier electronic states of both wide and narrow band gap AGNRs. First-principles calculations provide insight into substrate induced screening effects, which result in a width-dependent band gap reduction for substrate-supported AGNRs. The strategy reported here provides a unique opportunity to elucidate the electronic properties of various kinds of graphene nanomaterials supported on metal substrates.