1,020 research outputs found
Giant Rashba splitting of quasi-1D surface states on Bi/InAs(110)-(21)
Electronic states on the Bi/InAs(110)-(21) surface and its
spin-polarized structure are revealed by angle-resolved photoelectron
spectroscopy (ARPES), spin-resolved ARPES, and density-functional-theory
calculation. The surface state showed quasi-one-dimensional (Q1D) dispersion
and a nearly metallic character; the top of the hole-like surface band is just
below the Fermi level. The size of the Rashba parameter ()
reached quite a large value (5.5 eV\AA). The present result would provide
a fertile playground for further studies of the exotic electronic phenomena in
1D or Q1D systems with the spin-split electronic states as well as for advanced
spintronic devices.Comment: 8 pages (double column), 7 figures and 1 tabl
Giant Anisotropy of Spin-Orbit Splitting at the Bismuth Surface
We investigate the bismuth (111) surface by means of time and angle resolved
photoelectron spectroscopy. The parallel detection of the surface states below
and above the Fermi level reveals a giant anisotropy of the Spin-Orbit (SO)
spitting. These strong deviations from the Rashba-like coupling cannot be
treated in perturbation theory. Instead, first
principle calculations could accurately reproduce the experimental dispersion
of the electronic states. Our analysis shows that the giant anisotropy of the
SO splitting is due to a large out-of plane buckling of the spin and orbital
texture.Comment: 5 pages, 4 figure
Orbifold Models in M-Theory
Among orbifold compactifications of -theory, we examine
models containing the particle physics Standard Model in four-dimensional
spacetimes, which appear as fixed subspaces of the ten-dimensional spacetimes
at each end of the interval, , spanning the
dimension. Using the projection to break the gauge symmetry in each
of the four-planes and a limiting relation to corresponding heterotic string
compactifications, we discuss the restrictions on the possible resulting gauge
field and matter spectra. In particular, some of the states are non-local: they
connect two four-dimensional Worlds across the dimension.
We illustrate our programmable calculations of the matter field spectrum,
including the anomalous U(1) factor which satisfies a universal Green-Schwarz
relation, discuss a Dynkin diagram technique to showcase a model with
gauge symmetry, and discuss generalizations to
higher order orbifolds.Comment: 23 pages, 2 figures, 4 tables; LaTeX 3 time
Topological phase diagram and saddle point singularity in a tunable topological crystalline insulator
We report the evolution of the surface electronic structure and surface
material properties of a topological crystalline insulator (TCI) Pb1-xSnxSe as
a function of various material parameters including composition x, temperature
T and crystal structure. Our spectroscopic data demonstrate the electronic
groundstate condition for the saddle point singularity, the tunability of
surface chemical potential, and the surface states' response to circularly
polarized light. Our results show that each material parameter can tune the
system between trivial and topological phase in a distinct way unlike as seen
in Bi2Se3 and related compounds, leading to a rich and unique topological phase
diagram. Our systematic studies of the TCI Pb1-xSnxSe are valuable materials
guide to realize new topological phenomena.Comment: 10 pages, 7 figures. Expanded version of arXiv:1403.156
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