Banca de DEFESA: SIDNEY MARQUES GUEDES DOS SANTOS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE: SIDNEY MARQUES GUEDES DOS SANTOS
DATA: 22/06/2026
HORA: 09:00
LOCAL: Remota
TÍTULO: SIMULAÇÕES COMPUTACIONAIS DE SISTEMAS HÍBRIDOS CₙH₂@SWCNT E ALÓTROPOS BIDIMENSIONAIS DE CARBONO: CADEIAS LINEARES DE CARBONO CONFINADAS EM NANOTUBOS DE PAREDE SIMPLES SOB CAMPO ELÉTRICO EXTERNO E TRIPENTAFENO DOPADO COM BORO E NITROGÊNIO
PALAVRAS-CHAVES: nanotubos de carbono; carbinas; poliinas; campo elétrico; dopagem em tripentafeno; teoria do funcional da densidade; materiais bidimensionais; engenharia do gap de energia; espectr
PÁGINAS: 130
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Física
RESUMO:

In this work, a theoretical study based on Density Functional Theory
(DFT) was carried out on linear hydrogen-saturated carbon chains (CₙH₂, with
n = 4, 6, and 8) confined inside single-walled carbon nanotubes of the zigzag
(8,0) and armchair (5,5) types under the influence of a transverse external
electric field. The structural and electronic properties of these systems were
investigated, with emphasis on bond length alternation (BLA), transverse
deformation, charge transfer, and the electronic response to the applied field.
The results showed that systems based on the (8,0) nanotube exhibit a more
pronounced structural and electronic response compared to the (5,5) systems,
including greater charge redistribution, stronger BLA reduction, and higher
sensitivity of the electronic band gap. Despite these modifications, all systems
preserved the polyyne character of the chains and maintained a finite band gap
throughout the investigated field range. The analysis of the band structure and
projected density of states revealed that the electronic response is
predominantly governed by the host nanotube, while the carbyne chain acts as
a secondary electronic perturbation. An essentially reversible structural
behavior was also observed after removal of the electric field.
Additionally, the effects of substitutional boron and nitrogen doping on two-
dimensional carbon allotropes of the tripentaphene (TPH) type were
investigated. The results indicated that doping significantly modifies the
electronic properties of these systems, promoting transitions between metallic
and semiconducting behaviors, as well as modulation of the band gap. The
obtained results highlight the potential of these hybrid materials, as well as two-
dimensional allotropes, for applications in nanoelectronics and the engineering
of materials with tunable electronic properties.

MEMBROS DA BANCA:
Interno - 1548848 - EDUARDO COSTA GIRAO
Interno - 3374421 - LUCAS SOARES MARINHO
Externo ao Programa - 1352407 - RAFAEL DE ALENCAR ROCHA
Presidente - 1340442 - RAMON SAMPAIO FERREIRA