43,211 research outputs found
Intra- and Interband Electron Scattering in the Complex Hybrid Topological Insulator Bismuth Bilayer on BiSe
The band structure, intra- and interband scattering processes of the
electrons at the surface of a bismuth-bilayer on BiSe have been
experimentally investigated by low-temperature Fourier-transform scanning
tunneling spectroscopy. The observed complex quasiparticle interference
patterns are compared to a simulation based on the spin-dependent joint density
of states approach using the surface-localized spectral function calculated
from first principles as the only input. Thereby, the origin of the
quasiparticle interferences can be traced back to intraband scattering in the
bismuth bilayer valence band and BiSe conduction band, and to interband
scattering between the two-dimensional topological state and the
bismuth-bilayer valence band. The investigation reveals that the bilayer band
gap, which is predicted to host one-dimensional topological states at the edges
of the bilayer, is pushed several hundred milli-electronvolts above the Fermi
level. This result is rationalized by an electron transfer from the bilayer to
BiSe which also leads to a two-dimensional electron state in the
BiSe conduction band with a strong Rashba spin-splitting, coexisting
with the topological state and bilayer valence band.Comment: 11 pages, 5 figure
An Optical-Lattice-Based Quantum Simulator For Relativistic Field Theories and Topological Insulators
We present a proposal for a versatile cold-atom-based quantum simulator of
relativistic fermionic theories and topological insulators in arbitrary
dimensions. The setup consists of a spin-independent optical lattice that traps
a collection of hyperfine states of the same alkaline atom, to which the
different degrees of freedom of the field theory to be simulated are then
mapped. We show that the combination of bi-chromatic optical lattices with
Raman transitions can allow the engineering of a spin-dependent tunneling of
the atoms between neighboring lattice sites. These assisted-hopping processes
can be employed for the quantum simulation of various interesting models,
ranging from non-interacting relativistic fermionic theories to topological
insulators. We present a toolbox for the realization of different types of
relativistic lattice fermions, which can then be exploited to synthesize the
majority of phases in the periodic table of topological insulators.Comment: 24 pages, 6 figure
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