Εξειδίκευση τύπου :	Άρθρο σε επιστημονικό περιοδικό
Τίτλος:	High temperature stability, metallic character and bonding of the Si2BN planar structure
Δημιουργός/Συγγραφέας:	Fthenakis, Zacharias G Jaishi, Meghnath Narayanan, Badri [EL] Ανδριώτης, Α. Ν.[EN] Andriotis, A. N. Menon, Madhu
Ημερομηνία:	2021-03-10
Γλώσσα:	Αγγλικά
ISSN:	0953-8984 1361-648X
DOI:	10.1088/1361-648X/abdbe9
Άλλο:	33445169
Περίληψη:	The family of monolayered Si2BN structures constitute a new class of 2D materials exhibiting metallic character with remarkable stability. Topologically, these structures are very similar to graphene, forming a slightly distorted honeycomb lattice generated by a union of two basic motifs with AA and AB stacking. In the present work we study in detail the structural and electronic properties of these structures in order to understand the factors which are responsible for their structural differences as well as those which are responsible for their metallic behavior and bonding. Their high temperature stability is demonstrated by the calculations of finite temperature phonon modes which show no negative contributions up to and beyond 1000 K. Presence of the negative thermal expansion coefficient, a common feature of one-atom thick 2D structures, is also seen. Comparison of the two motifs reveal the main structural differences to be the differences in their bond angles, which are affected by the third nearest neighbor interactions ofcis-transtype. On the other hand, the electronic properties of these two structures are very similar, including the charge transfers occurring between orbitals and between atoms. Their metallicity is mainly due to thepzorbitals of Si with a minor contribution from thepzorbitals of B, while the contribution from thepzorbitals of N atoms is negligible. There is almost no contributions from the Npzelectrons to the energy states near the Fermi level, and they form a band well below it. I.e., thepzelectrons of N are localized mostly at the N atoms and therefore cannot be considered as mobile electrons of thepzcloud. Moreover, we show that due to the relative positions in the energy axis of the atomic energies of thepzorbitals of B, N and Si atoms, the density of states (DOS) of Si2BN can be considered qualitatively as a combination of the DOS of planar hexagonal BN (h-BN) and hypothetically planar silicene (ph-Si). As a result, the Si2BN behaves electronically at the Fermi level as slightly perturbed ph-Si, having very similar electronic properties as silicene, but with the advantage of having kinetic stability in planar form. As for the bonding, the Si-Si bonds are covalent, while theπback donation mechanism occurs for the B-N bonding, in accordance with the B-N bonding in h-BN.
Τίτλος πηγής δημοσίευσης:	Journal of physics. Condensed matter : an Institute of Physics journal
Τόμος/Κεφάλαιο:	33
Τεύχος:	16
Σελίδες:	165001
Θεματική Κατηγορία:	[EL] Φυσική και θεωρητική χημεία[EN] Physical and theoretical chemistry [EL] Νανοτεχνολογία[EN] Nanotechnology
Λέξεις-Κλειδιά:	2D materials Electronic structure First principles calculations Molecular Dynamics Nano electronics
EU Grant:	MIS 5002772 NSRF 2014–2020
Κάτοχος πνευματικών δικαιωμάτων:	© 2021 IOP Publishing Ltd
Ηλεκτρονική διεύθυνση στον εκδότη (link):	https://iopscience.iop.org/article/10.1088/1361-648X/abdbe9#artAbst
Σημειώσεις:	ZGF acknowledges support by the project FLAG-ERA-'GATES' (JTC-PCI2018-093137, MIS 5002772), funded by the Operational Programme 'Competitiveness, Entrepreneurship and Innovation' (NSRF 2014–2020) and co-financed by Greece and the European Union (European Regional Development Fund).
Εμφανίζεται στις συλλογές:	Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο