چكيده به لاتين
Abstract:
A new field has emerged in condensed-matter physics based on the realization that the spin-orbit interaction can leads to discover topological insulating electronic phases. The easiest way to describe a topological insulator is as an insulator that always has a metallic boundary when placed next to an ‘ordinary’ insulator. With the use of topological insulators, some interesting quasiparticles such as Marjorana fermions can be created that are of great importance for quantum computing.
Stanene is composed of tin atoms arranged in a single, hexagonal layer, in a manner similar to graphene. That was investigate as topological insulators and emphasized that they exhibit like quantum spin-Hall insulators due to their spin–orbit coupling (SOC). These new QSH insulators have extraordinarily large bulk gaps (0.3 eV); their QSH states can be effectively tuned by chemical functionalization and by external strain. A novel structure of stanene with dumbbell units was named DB stanene that it is a two-dimensional topological insulator. The calculated cohesive energy per Sn atom for DB stanene is 0.18 eV larger than that of LB stanene, indicating that DB stanene is more stable.
In this thesis, the electronic and magnetic properties of DB stanene, is discussed by using density functional theory with computional code FPLO and GGA approximation. DB stanene has hexagonal structure with number of space group 191.
In this work investigate the electronic properties of DB stanene under applying uniaxial strain on the unit cell. Also we study the magnetic properties of unit cell and super cell of DB stanene in the absence and presence of vacancy and show that DB stanene is unmagnetic material. The total energy, total magnetic energy and moment, the band structure and Density of states were calculated.
Keywords: Topological insulator, Spin-orbit coupling, QSH insulator, DB stanene, Vacancy, strain, Density Functional Theory
