Banca de DEFESA: MAYKON VINÍCIUS MONTEIRO DE ARAÚJO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE: MAYKON VINÍCIUS MONTEIRO DE ARAÚJO
DATA: 31/01/2024
HORA: 14:00
LOCAL: Remota
TÍTULO: Numerical studies of Mott transitions and thermoelectric properties of correlated compounds
PALAVRAS-CHAVES: Charge density wave, Mott transition, Seebeck coefficient, anisotropic triangular lattice, Quantum Monte Carlo.
PÁGINAS: 112
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Física
RESUMO:

This thesis is aimed at the study of transport and thermal properties of two-dimensional
systems presenting strong electron-electron or electron-phonon interactions, which is
performed via unbiased quantum Monte Carlo simulations. In the first part, we analyze
the single-band t-t 0 Holstein model in the square lattice, adding a next-nearest neighbor
hopping t 0 in order to play the role of the external pressure, which offers insights about
the competition and interplay between charge-density wave and superconductivity in
quasi2D compounds, such as transition-metal dichalcogenides (TMDs). By investigating
the charge-charge correlation functions, we obtain the behavior of the critical
temperature as a function of t 0 , and from compressibility analysis, we show that a first-
order metal-toinsulator phase transition occurs. We also provide a low-temperature
phase diagram for the model. In the second part, we investigate thermoelectric
properties for the two-dimensional Hubbard model on different geometries (square,
triangular, and honeycomb lattices) for different electronic densities and interaction
strengths. Using Determinantal Quantum Monte Carlo (DQMC) simulations, we find
the following key results: (a) the bi-partiteness iii of the lattice affects the doping
dependence of the Seebeck coefficient S; (b) strong electronic correlations can greatly
enhance S and produce non-trivial sign changes as a function of doping especially in the
vicinity of the Mott insulating phase; (c) S(T) near half filling can show non-monotonic
behavior as a function of temperature. Finally, as our ongoing work, we investigate the
transport properties for the twodimensional Hubbard model on an anisotropic
triangular lattice, using DQMC simulations, providing a ground state phase diagram for
the model and leaving as perspective, the investigations of the magnetic nature of the
phases involved.

MEMBROS DA BANCA:
Externo ao Programa - 389.794.383-20 - ANDRÉ DE PINHO VIEIRA - USP
Interno - 1548848 - EDUARDO COSTA GIRAO
Interno - 2643659 - IRISMAR GONCALVES DA PAZ
Presidente - 423297 - JOSE PIMENTEL DE LIMA
Externo à Instituição - MARCELLO BARBOSA DA SILVA NETO - UFRJ
Externo ao Programa - 010.453.033-21 - NATANAEL DE CARVALHO COSTA - UFRJ
Externo ao Programa - 231.899.753-53 - RAIMUNDO NOGUEIRA DA COSTA FILHO - UFC