Reminder TODAY: CMSP Seminar (Atomistic Simulation Seminar Series) 18 November, 11:00AM, by Alaa Mohammed Idris

[CMSP Seminars Secretariat]

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CMSP Seminar (Atomistic Simulation Seminar Series)
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*Monday, 18 November 2024, 11:00AM*
*/Budinich Lecture Hall (Leonardo Building)/*/
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/Zoom: https://zoom.us/meeting/register/tJEucu2tqT8uGNYvpgXUFeLDWBQUA5z0bwV0
<https://zoom.us/meeting/register/tJEucu2tqT8uGNYvpgXUFeLDWBQUA5z0bwV0> /

Speaker:*  Alaa Mohammed Idris*** (University of the Basque Country)

Title: *Formation of Europium-transition metal surface compound and 
protection of Eu below hexagonal boron nitride (h-BN) *

Abstract:

We examined the modifications in the electronic and structural 
properties of hexagonal boron nitride (hBN) grown by the CVD process on 
curved transition metal substrates, namely c-Pt(111) and c-Ni(111) 
crystals, both before and after Europium (Eu) intercalation. Numerous 
emerging devices are proposed to rely on 2D materials such as Graphene, 
hexagonal boron nitride, and others. These materials are generally grown 
by CVD processes on metal substrates such as Copper, Nickel, or 
Platinum. The quality of growth significantly relies on both the 
crystallinity of the substrate and the interaction between the overlayer 
and the substrate. The characteristics of the interface can be altered 
by adjusting the crystal structure and step density of the substrate. 
This was demonstrated through the growth of hBN on curved crystals, 
where the substrate faceting varied between strong (Ni) [1], 
intermediate (Rh) [2] and weak (Pt) [3]. Experimentally, the structural 
properties were characterized using Low-energy electron diffraction 
(LEED) and scanning tunneling microscopy (STM). Stable facets were 
observed to form during hBN growth on the substrates. However, after Eu 
intercalation, changes in the stable facets were observed. The LEED 
detected the formation of Eu-TM alloy. Furthermore, the electronic 
properties were carried out using x-ray photoelectron spectroscopy (XPS) 
and angle-resolved photoemission spectroscopy (ARPES). Additionally, we 
investigated the ability of the hBN layer to protect Eu on both curved 
Pt(111) and Ni(111) substrates. Our results suggest that the protective 
effect of the hBN layer on Eu was incomplete and exhibited variation 
along the curved surfaces of the crystals. Specifically, on c-Pt(111), 
better Eu protection was noted at the (111) surface compared to the 
steps. Conversely, on c-Ni(111), the opposite trend was observed. This 
variation could potentially be attributed to the influence of the 
mismatch between the hBN and the substrates. The incomplete protection 
of Eu due to defects and growth boundaries in the hBN layer led to the 
oxidation of Eu. Theoretical calculations were conducted to gain further 
insights into the formation of stable surface facets by investigating 
the structural properties of hBN on various Pt vicinal surfaces.

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/References
1- Fern´andez, Laura, et al. 2D Materials (2019) 6, 025013.
2- Ali, Khadiza, et al. Adv. Sci. (2021) 8, 2101455.
3- Bakhit, Alaa Mohammed Idris, et al. Science Talks (2022) 4, 100071.
4- Bakhit, Alaa Mohammed Idris, et al. Nanoscale (2023), 15.27, 
11517-11528./

http://www.ictp.it/research/cmsp.aspx

The Abdus Salam International Centre for Theoretical Physics
https://www.ictp.it/

    
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