Sagisaka, Keisuke;
Kusawake, Tomoko;
Bowler, David R;
Ohno, Shinya;
(2023)
Emergence of metallic surface states and negative differential conductance in thin β-FeSi₂ films on Si(001).
Journal of Physics: Condensed Matter
, 35
(13)
, Article 135001. 10.1088/1361-648X/acb628.
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Abstract
The electronic properties of the surface of $\beta$-FeSi$_2$ have been debated for a long \textcolor{blue}. We studied the surface states of $\beta$-FeSi$_2$ films grown on Si(001) substrates using scanning tunnelling microscopy (STM) and spectroscopy (STS), with the aid of density functional theory (DFT) calculations. STM simulations using the surface model proposed by Romanyuk \textit{et al.} [Phys. Rev. B 90, 155305 (2014)] reproduce the detailed features of experimental STM images. The result of STS showed metallic surface states in accordance with theoretical predictions. The Fermi level was pinned \textcolor{blue}{by a} surface state that appeared in the bulk band gap of the $\beta$-FeSi$_2$ film, irrespective of \textcolor{blue}{the polarity of the} substrate. We also observed negative differential conductance at $\sim$0.45 eV above the Fermi level in STS measurements performed at 4.5 K, reflecting the presence of an energy gap in the unoccupied surface states of $\beta$-FeSi$_2$.
| Type: | Article |
|---|---|
| Title: | Emergence of metallic surface states and negative differential conductance in thin β-FeSi₂ films on Si(001) |
| Location: | England |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1088/1361-648X/acb628 |
| Publisher version: | http://dx.doi.org/10.1088/1361-648X/acb628 |
| Language: | English |
| Additional information: | As the Version of Record of this article is going to be/has been published on a subscription basis, this Accepted Manuscript will be available for reuse under a CC BY-NC-ND 3.0 licence after a 12 month embargo period. Although reasonable endeavours have been taken to obtain all necessary permissions from third parties to include their copyrighted content within this article, their full citation and copyright line may not be present in this Accepted Manuscript version. Before using any content from this article, please refer to the Version of Record on IOPscience once published for full citation and copyright details, as permission may be required. All third party content is fully copyright protected, unless specifically stated otherwise in the figure caption of the Version of Record. |
| Keywords: | Density functional theory calculations, Local density of states, Scanning Tunneling Microscopy, Scanning Tunneling Spectroscopy, Silicide thin films |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10164099 |
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