Banca de DEFESA: Fernando Marques de Oliveira Moucherek
Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.STUDENT : Fernando Marques de Oliveira Moucherek
DATE: 24/11/2022
TIME: 09:30
LOCAL: On-line
TITLE:
Physical properties of monolayer of OsSe2 in phase 1T′: Study via calculation of DFTKEY WORDS:
Key-Words: monolayers, DFT, 1T’ phase.
PAGES: 92
BIG AREA: Ciências Exatas e da Terra
AREA: Física
SUMMARY:
SUMMARY
After the isolation of graphene in 2004, scientists quickly showed that it has remarkable properties.
However, as the scientific understanding of graphene has matured, it has become clear that it also has
limitations: for example, graphene does not have a bandgap, making it unsuitable for use in optical -
electronic devices. This motivated explorations of materials in the form of monolayers beyond
graphene, which could incorporate functionality that graphene lacks. Transition metal dichalogenides
(TMDs) are prime candidates in this field. TMDs have a wide variety of properties accessible through
the choice of chalcogen atom, metal atom and atomic configuration (1H, 1T and 1T'). Similar to
graphene, monolayer TMDs can be produced through mechanical exfoliation, however useful
applications will require the development of reliable methods for the synthesis and growth of
monolayers. In this work, I present a theoretical study, through DFT calculations, of the OsSe2
monolayers in the 1T' phase. Among other things, we sought to verify the stability of the material,
which was confirmed when studying the dispersion of phonons. The graph presents the acoustic and
optical branches well defined and with positive values defined which is a strong point in the sense of
verifying the stability of osmium diselenide. We studied the band structure where it was found that
the material has an indirect gap. Another analysis that was carried out is associated with the
thermodynamic properties, where so many quantities enter, it was found that the heat capacity
increases rapidly as the temperature increases in the range from 0 to 200K, reaching the Dulong-Petit
limit around 600K.
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