Direct observation of many-body charge density oscillations in a two-dimensional electron gas

Sessi, Paolo; Silkin, Viatcheslav M.; Nechaev, I. A.; Bathon, Thomas; El-Kareh, Lydia; Chulkov, Evgueni V.; Echenique, Pedro M.; Bode, Matthias

doi:10.1038/ncomms9691

Cited by 16 publications

(17 citation statements)

References 35 publications

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“…Simple 1-band systems can be analyzed directly, and this was first done for the surface states of noble metals [21,22,23,24,25] which have more recently been used to advance FT-STS as a probe for many-body effects [17,26]. However, more complicated systems require complementary information about the band structure, and the patterns observed can become extremely complex when scattering between multiple bands [3,19,27], and the possibility of selection rules for the allowed scattering processes [5,7,16,28], come into play.…”

Section: Introductionmentioning

confidence: 99%

Dispersing artifacts in FT-STS: a comparison of set point effects across acquisition modes

Grothe

et al. 2016

Nanotechnology

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Abstract. Fourier transform scanning tunnelling spectroscopy (FT-STS), or quasiparticle interference (QPI), has become an influential tool for the study of a wide range of important materials in condensed matter physics. However, FT-STS in complex materials is often challenging to interpret, requiring significant theoretical input in many cases, making it crucial to understand potential artifacts of the measurement. Here, we compare the most common modes of acquiring FT-STS data and show through both experiment and simulations that artifact features can arise that depend on how the tip height is stabilized throughout the course of the measurement. The most dramatic effect occurs when a series of dI/dV maps at different energies are acquired with simultaneous constant current feedback; here a feature that disperses in energy appears that is not observed in other measurement modes. Such artifact features are similar to those arising from real physical processes in the sample and are susceptible to misinterpretation.

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Section: Introductionmentioning

confidence: 99%

Dispersing artifacts in FT-STS: a comparison of set point effects across acquisition modes

Grothe

et al. 2016

Nanotechnology

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“…By means of STM, the life times [26,27] as well as the electron-phonon coupling parameter λ and the self-energy Σ [28] of surface states were determined. QPI also gave access to other many-body effects including coupling to surface plasmons [29] and different phonon modes [30][31][32]. As another approach by STM, Landau level spectroscopy offered access to 2D sample systems and their renormalized bands due to electron-phonon coupling [33,34].…”

Section: Introductionmentioning

confidence: 99%

Scanning Tunneling Spectroscopy of Subsurface Ag and Ge Impurities in Copper

Kotzott,

Bouhassoune,

Prüser

et al. 2021

Preprint

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We investigate single Ge and Ag impurities buried below a Cu(100) surface using low temperature scanning tunneling microscopy. The interference patterns in the local density of states are surface scattering signatures of the bulk impurities, which result from 3D Friedel oscillations and the electron focusing effect. Comparing the isoelectronic d scatterer Ag and the sp scatterer Ge allows to distinguish contributions from impurity scattering and the host. Energy-independent effective scattering phase shifts are extracted using a plane wave tight-binding model and reveal similar values for both species. A comparison with ab-initio calculations suggests incoherent sp scattering processes at the Ge impurity. As both scatterers are spectrally homogeneous, scanning tunneling spectroscopy of the interference patterns yields real-space signatures of the bulk electronic structure. We find a kink around zero bias for both species that we assign to a renormalization of the band structure due to many-body effects, which can be described with a Debye self-energy and a surprisingly high electron-phonon coupling parameter λ. We propose that this might originate from bulk propagation in the vicinity of the surface.

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“…33 Furthermore, it was shown that STM measurements can be used to provide insights into many-body interactions at the atomic scale. 34 Both of these experimental techniques have been widely used to quantify characteristics of silicene on various substrates. 33,[35][36][37] Therefore, it is worthwhile to investigate the dynamical many-body properties of silicene, thoroughly.…”

Section: Introductionmentioning

confidence: 99%

Many-body effects due to the electron–electron interaction in silicene under an applied exchange field: The case of valley–spin coupling

Mirzaei

Vazifehshenas

Salavati-fard

et al. 2020

Journal of Applied Physics

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We investigate the many-body effects induced by the electron-electron interaction in a valley-spin-polarized silicene under a perpendicularly applied exchange field. We calculate the real and imaginary parts of the self-energy within the leading order dynamical screening approximation where the screened interaction is obtained from the random phase approximation. Our study on the valley-and spin-dependent real and imaginary parts of the self-energy indicates that the different coupled valley-spin subbands may exhibit distinct characteristics. Moreover, we obtain the corresponding spectral functions and find that the plasmaron and quasiparticle peaks have different spectral weights and broadenings in all states. Interestingly, it seems that there are clear dependencies for the position and broadening of the peaks on valley-spin indexes. In addition, we study the effect of the electron-electron interaction on the renormalized velocity in the on-shell approximation and show that the renormalized velocity in gapped states becomes greater, and in gapless states, it becomes smaller as the wave vector grows.

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Direct observation of many-body charge density oscillations in a two-dimensional electron gas

Cited by 16 publications

References 35 publications

Dispersing artifacts in FT-STS: a comparison of set point effects across acquisition modes

Dispersing artifacts in FT-STS: a comparison of set point effects across acquisition modes

Scanning Tunneling Spectroscopy of Subsurface Ag and Ge Impurities in Copper

Many-body effects due to the electron–electron interaction in silicene under an applied exchange field: The case of valley–spin coupling

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