Scanning tunnelling spectroscopy of electron resonators

Abstract

The electronic structure of artificial Mn atom arrays on Ag(111) is characterized in detail with scanning tunnelling spectroscopy and spectroscopic imaging at low temperature. We demonstrate the degree to which variations in geometry may be used to control spatial and spectral distributions of surface state electrons confined within the arrays, how these are influenced by atoms placed within the structure and how the ability to induce spectral features at specific energies may be exploited through lineshape analyses to deduce quasiparticle lifetimes near the Fermi level. Through extensive comparison of dI/dV maps and spectra we demonstrate the utility of a model based upon twodimensional s-wave scatterers for describing and predicting the characteristics of specific resonators.

Decay of electronic excitations at metal surfaces

“…The absolute lifetimes of Ref. [198], however, are generally somewhat smaller than the data by Braun and Rieder. An extrapolation of the results of Ref.…”

“…57, we show the calculated results for Ag(1 1 1) in terms of G ee scaled by ðE À E F Þ À2 for energies from 0.1 to 1.1 eV [192]. We also display the experimental data of Kliewer et al [198] and Vitali et al [192]. The evaluated decay rate G ee due to interband and intraband transitions, the electronphonon contribution G ep and the decay rate due to all inelastic processes G total ¼ G ee þ G ep are shown separately.…”

“…However, this limitation can be circumvented. To this end, Kliewer et al constructed electron resonators by laterally moving adatoms on the surface with the STM tip [197,198] (Fig. 31a).…”

“…[198], the LDOS of the adatom arrays was calculated using a multiple-scattering technique introduced by Heller et al [199]. The calculations were extended to include an energy-dependent lifetime of the electronic states.…”

“…The gray shaded area of the plot marks the region where the surface state overlaps in energy with the projected bulk bands ( a Ref. [198]; b Ref. [192]).…”