Banca de QUALIFICAÇÃO: Carlos Derli Almeida Cornelio

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : Carlos Derli Almeida Cornelio
DATE: 19/04/2023
TIME: 14:00
LOCAL: IF
TITLE:

Confinamento de éxcitons de Moiré em bicamadas de van der Waals rotacionadas

KEY WORDS:

Transition Metal Dichalcogenides, Twisted van der Waals materials, Moiré Excitons

PAGES: 70
BIG AREA: Ciências Exatas e da Terra
AREA: Física
SUMMARY:

Abstract:

Misalignment in the layer stacking of twisted van der Waals materials leads to an in-plane superlattice known as the moiré pattern. Signatures of optical properties dominated by bound interlayer electron–hole pairs, known as moiré excitons, were experimentally detected in twisted transition metal dichalcogenide hetero-bilayers (MoSe2/WSe2). The such in-plane potential landscape for moiré excitons resembles an artificial honeycomb superlattice, resulting in a gapped Dirac-like band structure for low energies. Moreover, due to the different interlayer distances and stacking registries, forming different energy minima, a perpendicularly applied electric field can tune the moiré bands and even close the excitonic bandgap, forming a Dirac-like cone. Here we apply two position-dependent bias potentials in twisted MoSe2/WSe2 junction to demonstrate theoretically that quantum confinement dotlike and ringlike nanostructures can be electrostatically defined and, therefore, introducing an additional control in the moiré exciton trapping. The quantized moiré excitonic energy spectra and the wave functions obtained via the tight-binding model are compared with an analytical solution derived within the continuum model by using circularly symmetric potential.

BANKING MEMBERS:
Presidente - 3272139 - ALEXANDRE CAVALHEIRO DIAS
Interno - 407633 - DAVID LIMA AZEVEDO
Externo à Instituição - DIEGO RABELO DA COSTA - UFC
Externo à Instituição - TELDO ANDERSON DA SILVA PEREIRA - UFMT