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

Autor(es)

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]

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry C; v. 122, n. 35, p. 20483-20488, SEP 6 2018.
• Citações Web of Science: 5

Resumo

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)

• Processo FAPESP: 13/15112-9 - Estudo ab initio dos efeitos de ligantes na estrutura atômica, eletrônica e estabilidade de nanoclusters de metais de transição
• Beneficiário: Diêgo Guedes Sobrinho
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 17/11631-2 - CINE: desenvolvimento computacional de materiais utilizando simulações atomísticas, meso-escala, multi-física e inteligência artificial para aplicações energéticas
• Beneficiário: Juarez Lopes Ferreira da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Programa Centros de Pesquisa em Engenharia
• Processo FAPESP: 17/09077-7 - Estudo ab-initio das propriedades estruturais, eletrônicas, e ópticas de heteroestruturas de van der Waals
• Beneficiário: Rafael Besse
• Modalidade de apoio: Bolsas no Brasil - Doutorado