Seminários

Seminário de Matéria Condensada

O seminário de Matéria Condensada dessa semana será apresentado por
Tomé Schmidt, da Universidade Federal de Uberlândia. O título do
seminário é "Topological insulators protected by time-reversal and
crystal symmetry."

Data: quinta-feira, 6/11
Horário: 11h
Local: sala 201

Resumo: Topological insulators (TI) form a new quantum phase in
condensed matter physics, where protected states are present on the
edges of the material. Their properties are interesting for novel
technologies as well an emplacement for fundamental physics
understanding. The topological protected edge states of the first
discovered TIs were based on the preservation of time reversal
symmetry. The spin texture of surface metallic states of a 3D TI are
such that backscattering can not takes place, since the non degenerate
states are protected by time reversal symmetry.

Recently, topological crystalline insulator, a new class where states
are protected by lattice symmetry instead of by time-reversal symmetry
has been proposed.  We will show that monolayers of PbSe is a 2D
topological crystalline insulator, the first 2D system proposed in
this class. In this talk we will also present the fundamental concept
of topological insulator within the band theory formalism. We will
show the electronic and spin texture of 3D and 2D topological
insulators, and how the protected edge states are robust against
perturbations. The results are based on effective Rashba-like
hamiltonians and  first-principles calculations.