145 research outputs found
Origin of Magnetic Circular Dichroism in GaMnAs: Giant Zeeman Splitting versus Spin Dependent Density of States
We present a unified interpretation of experimentally observed magnetic
circular dichroism (MCD) in the ferromagnetic semiconductor (Ga,Mn)As, based on
theoretical arguments, which demonstrates that MCD in this material arises
primarily from a difference in the density of spin-up and spin-down states in
the valence band brought about by the presence of the Mn impurity band, rather
than being primarily due to the Zeeman splitting of electronic states.Comment: 4+ pages, 4 figure
Temperature dependence of the bandgap of Eu doped {ZnCdO/ZnO}30 multilayer structures
In situ Eu-doped {ZnCdO/ZnO}30 multilayer systems were grown on p-type
Si-substrates and on quartz substrates by plasma-assisted molecular beam
epitaxy. Various Eu concentrations in the samples were achieved by controlling
temperature of the europium effusion cell. The properties of as-grown and
annealed {ZnCdO/ZnO}30:Eu multilayers were investigated using secondary ion
mass spectrometry (SIMS) and X-ray diffraction methods. SIMS measurements
showed that annealing at 700{\deg}C and 900{\deg}C practically did not change
the Eu concentration and the rare earth depth profiles are uniform. It was
found that the band gap depends on the concentration of Eu and it was changed
by rapid thermal annealing. Varshni and Bose-Einstein equations were used to
describe the temperature dependence of the band gap of {ZnCdO/ZnO}30:Eu
multilayer structures and Debye and Einstein temperatures were obtained.Comment: 16 pages, 8 figures, 3 table
Observation of surface states on heavily indium doped SnTe(111), a superconducting topological crystalline insulator
The topological crystalline insulator tin telluride is known to host
superconductivity when doped with indium (SnInTe), and for low
indium contents () it is known that the topological surface states are
preserved. Here we present the growth, characterization and angle resolved
photoemission spectroscopy analysis of samples with much heavier In doping (up
to ), a regime where the superconducting temperature is increased
nearly fourfold. We demonstrate that despite strong p-type doping, Dirac-like
surface states persist
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