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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Size-Induced Phase Evolution of MoSe2 Nanoflakes Revealed by Density Functional Theory

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Besse, Rafael [1] ; Caturello, Naidel A. M. S. [2] ; Bastos, Carlos M. O. [1] ; Guedes-Sobrinho, Diego [2, 3] ; Lima, Matheus P. [4] ; Sipahi, Guilherme M. [1] ; Da Silva, Juarez L. F. [2]
Total Authors: 7
[1] Univ Sao Paulo, Sao Carlos Inst Phys, POB 369, BR-13560970 Sao Carlos, SP - Brazil
[2] Univ Sao Paulo, Sao Carlos Inst Chem, POB 780, BR-13560970 Sao Carlos, SP - Brazil
[3] Technol Inst Aeronaut, Dept Phys, BR-12228900 Sao Jose Dos Campos, SP - Brazil
[4] Univ Fed Sao Carlos, Dept Phys, BR-13565905 Sao Carlos, SP - Brazil
Total Affiliations: 4
Document type: Journal article
Source: Journal of Physical Chemistry C; v. 122, n. 35, p. 20483-20488, SEP 6 2018.
Web of Science Citations: 5

The control of the relative stability between trigonal prismatic and octahedral structures in transition-metal dichalcogenides (TMDs) is an important step toward technological applications of 2D TMDs materials, where the electronic properties have a strong dependence on the structural phase and size effects. We report a density functional theory investigation of the size effect on the relative phase stability of stoichiometric (MoSe2)(n) nanoflakes with parallelogram shape for n = 15, 63, 108, 130, 154, 192. We found that the octahedral phase adopts a distorted configuration, which is driven by the Peierls transition mechanism, and, as expected, the Mo-terminated edges of the trigonal prismatic nanoflakes exhibit a strong reconstruction. Furthermore, for the smallest nanoflakes, the octahedral phase has the lowest energy, but with increasing the nanoflake size, the trigonal prismatic phase becomes the most stable. From our results and analyses, this transition is shown to be mainly caused by a difference in edge formation energy of the two structural configurations. Although the physical trends have been obtained for MoSe2 nanoflakes, we expect that similar trends might be observed in different 2D TMDs. (AU)

FAPESP's process: 13/15112-9 - Ab initio study of the effects of ligands on the atomic structure, electronic stability and transition metal nanoclusters
Grantee:Diêgo Guedes Sobrinho
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 17/09077-7 - Ab-initio study of the structural, electronic, and optical properties of van der Waals heterostructures
Grantee:Rafael Besse
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 17/11631-2 - Computational material science and chemistry
Grantee:Juarez Lopes Ferreira da Silva
Support type: Research Grants - Research Centers in Engineering Program