Estudo de interfaces entre isolantes topológicos e semicondutores

Abstract

Condensed matter physics is a very diverse area of physics, closely linked to mathematics and with discoveries with great potential for applications and technological innovations. Topological insulators are systems in condensed matter physics that present symmetry protected topological states at the interface with trivial insulators. In this thesis we seek to understand the behavior of these materials, topological insulators, when they form interfaces and heterostructures with distinct semiconductors. We analyze how these surface states are affected due to the interaction of these materials in these new structures. We analyzed interfaces and heterostructures formed from topological insulator Bi2Se3 with III-V semiconductors. The electronic properties are computed using first principles calculations based on the density functional theory (DFT). For a better under standing of the physical phenomena involved we also used a low energy effective Hamiltonian model. We verified that the topological states are affected by the interface trivial material. Charge transfer, trivial interface polarization, internal electric field are some of the effects that affect the protected interface states. We also observe that the topological states Fermi velocities as well the spin textures are strongly modified due to the hibridization of the topological states with trivial states at the interface.