Quantum-well and modified image-potential states in thin Pb(111) films: an estimate for the local work function
| Autor: | A. Yu. Aladyshkin |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Condensed Matter - Materials Science
Materials science Condensed Matter - Mesoscale and Nanoscale Physics Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences Conductance 02 engineering and technology Substrate (electronics) 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Molecular physics Spectral line Mesoscale and Nanoscale Physics (cond-mat.mes-hall) 0103 physical sciences Microscopy General Materials Science Work function 010306 general physics 0210 nano-technology Spectroscopy Quantum well Quantum tunnelling |
| Popis: | Quantum-confined electronic states such as quantum-well states (QWS) inside thin Pb(111) films and modified image-potential states (IPS) above the Pb(111) films grown on Si(111)7$\times$7 substrate were studied by means of low-temperature scanning tunnelling microscopy (STM) and spectroscopy (STS) in the regime of constant current $I$. By plotting the position of the $n-$th emission resonances $U^{\,}_n$ versus $n^{2/3}$ and extrapolating the linear fit for the dependence $U^{\,}_n(n^{2/3})$ in the high-$n$ limit towards $n=0$, we estimate the local work function for the Pb(111) film: $W\simeq 3.8\pm 0.1\,$eV. We experimentally demonstrate that modifications of the shape of the STM tip can change the number of the emission peaks associated with the resonant tunnelling via quantized IPS levels for the same Pb terrace; however it does not affect the estimate of the local work function for the flat Pb terraces. We observe that the maxima in the spectra of the differential tunnelling conductance $dI/dU$ related to both the QWS and the modified IPS resonances are less pronounced if the STM tip becomes more blunt. 14 pages, 7 figures |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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