Emergence of a non-bulk hexagonal Fe$_2$S$_2$ single layer via phase transformation
Fuente:
arXiv
Enregistré dans:
| Auteurs principaux: | , , , , , , , , , , |
|---|---|
| Format: | Preprint |
| Publié: |
2026
|
| Sujets: | |
| Accès en ligne: | |
| Tags: |
Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
|
| _version_ | 1866910160457302016 |
|---|---|
| author | Safeer, Affan Beida, Wejdan Oberbauer, Felix Atodiresei, Nicolae Bihlmayer, Gustav Wolfertz, Max Schlichte, Chiara Jolie, Wouter Blügel, Stefan Fischer, Jeison Michely, Thomas |
| author_facet | Safeer, Affan Beida, Wejdan Oberbauer, Felix Atodiresei, Nicolae Bihlmayer, Gustav Wolfertz, Max Schlichte, Chiara Jolie, Wouter Blügel, Stefan Fischer, Jeison Michely, Thomas |
| contents | Two-dimensional materials can stabilize crystal structures that are absent from their bulk counterparts, offering opportunities for materials design. Here, we report the synthesis of a previously unknown hexagonal Fe$_2$S$_2$ single layer with $β$-CuI structure, a buckled layer of two vertically stacked FeS honeycomb lattices, realized by thermally induced transformation of single layer mackinawite grown on graphene/Ir(111). In situ scanning tunneling microscopy and low-energy electron diffraction reveal a transition from a tetragonal to a hexagonal lattice accompanied by distinct morphological and electronic signatures. The hexagonal Fe$_2$S$_2$ forms reproducibly upon annealing and represents a new structural motif within the Fe-S material family. First-principles calculations identify the $β$-CuI structure as most consistent with experiment. The calculations suggest that on-site Coulomb interactions and magnetic order are relevant to understanding the stability of the new 2D Fe-S compound. The preferred nucleation of single-layer mackinawite, despite being energetically disfavored, is speculated to result from its low edge energy, analogous to the 3D case. Our results establish Fe$_2$S$_2$ as a platform for exploring structural polymorphism in two dimensions and demonstrate that reduced dimensionality can stabilize crystal structures not accessible in bulk materials. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2604_21613 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Emergence of a non-bulk hexagonal Fe$_2$S$_2$ single layer via phase transformation Safeer, Affan Beida, Wejdan Oberbauer, Felix Atodiresei, Nicolae Bihlmayer, Gustav Wolfertz, Max Schlichte, Chiara Jolie, Wouter Blügel, Stefan Fischer, Jeison Michely, Thomas Materials Science Mesoscale and Nanoscale Physics Two-dimensional materials can stabilize crystal structures that are absent from their bulk counterparts, offering opportunities for materials design. Here, we report the synthesis of a previously unknown hexagonal Fe$_2$S$_2$ single layer with $β$-CuI structure, a buckled layer of two vertically stacked FeS honeycomb lattices, realized by thermally induced transformation of single layer mackinawite grown on graphene/Ir(111). In situ scanning tunneling microscopy and low-energy electron diffraction reveal a transition from a tetragonal to a hexagonal lattice accompanied by distinct morphological and electronic signatures. The hexagonal Fe$_2$S$_2$ forms reproducibly upon annealing and represents a new structural motif within the Fe-S material family. First-principles calculations identify the $β$-CuI structure as most consistent with experiment. The calculations suggest that on-site Coulomb interactions and magnetic order are relevant to understanding the stability of the new 2D Fe-S compound. The preferred nucleation of single-layer mackinawite, despite being energetically disfavored, is speculated to result from its low edge energy, analogous to the 3D case. Our results establish Fe$_2$S$_2$ as a platform for exploring structural polymorphism in two dimensions and demonstrate that reduced dimensionality can stabilize crystal structures not accessible in bulk materials. |
| title | Emergence of a non-bulk hexagonal Fe$_2$S$_2$ single layer via phase transformation |
| topic | Materials Science Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2604.21613 |