Supervisor: Luca F. Tocchio
In this project, the student will address electronic systems where a strong electron-electron repulsion leads to new fascinating phenomena, like high-temperature superconductivity. Generalizations of the Hubbard model, that treats the kinetic and the interaction terms of the electrons on the same footing are considered; since these models are, in general, not exactly solvable, a numerical approach is necessary.
The student will learn and apply the variational Monte Carlo method, where suitable approximations of the ground-state wave functions are constructed. One topic of interest are the iron-pnictide high-temperature superconductors. Here, multiband extension of the Hubbard models will be addressed to understand the nature of the superconductive pairing and its relation with the different orbitals of the Fe atoms that are involved in the chemical bonding. Another topic are twisted bilayer heterostructures. These artifical materials have a high degree of parameter tunability that can be controlled in experiments and exhibit superconductivity and exotic quantum phases.
Generalization of the Hubbard model will be addressed to investigate the presence of charge/spin/orbital orders in the insulating states, as well as the nature of the superconductive pairing.