Propriedades de transporte em sistemas com interação elétron-elétron, elétron-rede e mágnon-rede

Abstract

In this work, the electronic dynamics under the influence of Coulombic interaction and the effect of interaction with the lattice using the SSH model were studied. Additionally, the magnon-lattice pair and the transfer of quantum states with correlated disorder were investigated. In the context of Coulomb interaction, the electron-electron term in a one dimensional lattice creates a sub-band of bound states, initially decoupling from the main band of states for U = 8, also observed for U = 12. The Hamiltonian allows for the consideration of local and non-local electron-electron interaction terms. The emergence of a new sub-band due to interaction between nearest neighbors and the broadening of this sub-band due to local interaction between particles can be observed. The system’s dynamics under the influence of an external electric field show that particle interaction promotes coherent motion, resulting in oscillation modes with doubled frequency. Electronic propagation under the effect of electron-lattice interaction was investigated in the cubic nonlinearity formalism. The coupling between the electron and the lattice was introduced through the hopping distribution. The coupled equations for the electron-lattice system were solved, and the electronic position as a function of time was calculated. A detailed investigation of the electron and lattice dynamics was conducted for a wide range of electron-lattice coupling intensities. The results demonstrate that, depending on the initial condition and the intensity of the electron-lattice interaction, the formation of the electron-lattice pair is possible. The results also reveal that, depending on the initial velocity of the lattice and the degree of the electron-lattice term, repulsion between lattice deformation and the electron is observed. In the study involving magnon-lattice interaction in a nonlinear Morse chain, coupling between the magnon and the lattice was achieved through the exchange term in the Heisenberg Hamiltonian. The results indicate that the formation of the magnon-lattice pair occurs for specific interaction values dependent on initial conditions. It was also observed that with an increase in the time difference between magnon propagation and the lattice, the values required to promote coupling decrease. Lastly, in the final study, the transfer of quantum states was explored under the influence of disordered magnetic fields and exchange couplings with long-range correlated disorder. The transmitted magnon is in a lattice in the ferromagnetic ground state. For a non-zero field, Anderson localization is induced in the channel, but better-than-classical transmission is still possible for moderate field intensity.