Estudo da estrutura eletrônica da bicamada de grafeno rotacionada e intercalada com o átomo de Li

Abstract

Graphene consists of a layer of carbon atoms that are compacted in network two-dimensional hexagonal (2D). The stacking of two monolayers forms the graphene bilayer and the realization of the rotation between the monolayers makes the appearance of the twisted bilayer graphene, that due to promising experimental results of this system rotated to the magic angles, the phenomenon of superconductivity was observed in 1.1 ◦ , which opened doors for further studies in 2D materials. In this work, we dedicate our studies to the twisted bilayer graphene system with the angle of 21.8

◦ and also for the same system intercalated with the atom of lithium, using calculations of first principles based on density functional theory (DFT) using the method of full potential linearized augmented plane waves (FP-LAPW), that are implemented in the WIEN2K computational package. With the realization of the rotation, we have the Moiré pattern and we get the Moiré unit cell, which is composed of 28 carbon atoms. To understand the electronic structure of both materials, we calculate the densisty of states, band structure and electronic density. Our results from the twisted bilayer graphene show us that the two Van Hove peaks around Fermi energy, in density of state, get closer. The bands close to the Fermi energy in the M-K direction it has a linear dispersion. When we intercalate with Li, we observe a displacement of the Fermi energy, where it shows an electron transfer to the twisted bilayer graphene. In conclusion, our work shows the tendency of the system to become superconducting as the angle goes towards the magic angles.