114 research outputs found
Band-to-band transitions, selection rules, effective mass and exciton binding energy parameters in monoclinic \beta-Ga2O3
We employ an eigen polarization model including the description of direction
dependent excitonic effects for rendering critical point structures within the
dielectric function tensor of monoclinic \beta-Ga2O3 yielding a comprehensive
analysis of generalized ellipsometry data obtained from 0.75 eV--9 eV. The
eigen polarization model permits complete description of the dielectric
response, and we obtain single-electron and excitonic band-to-band transition
anisotropic critical point structure model parameters including their
polarization eigenvectors within the monoclinic lattice. We compare our
experimental analysis with results from density functional theory calculations
performed using a recently proposed Gaussian-attenuation-Perdue-Burke-Ernzerhof
hybrid density functional, and we present and discuss the order of the
fundamental direct band-to-band transitions and their polarization selection
rules, the electron and hole effective mass parameters for the three lowest
band-to-band transitions, and their exciton binding energy parameters, in
excellent agreement with our experimental results. We find that the effective
masses for holes are highly anisotropic and correlate with the selection rules
for the fundamental band-to-band transitions, where the observed transitions
are polarized closely in the direction of the lowest hole effective mass for
the valence band participating in the transition
Electron effective mass in Sn-doped monoclinic single crystal -gallium oxide determined by mid-infrared optical Hall effect
The isotropic average conduction band minimum electron effective mass in
Sn-doped monoclinic single crystal -GaO is experimentally
determined by mid-infrared optical Hall effect to be
combining investigations on () and () surface cuts. This result
falls within the broad range of values predicted by theoretical calculations
for undoped -GaO. The result is also comparable to recent
density functional calculations using the
Gaussian-attenuation-Perdue-Burke-Ernzerhof hybrid density functional, which
predict an average effective mass of (arXiv:1704.06711
[cond-mat.mtrl-sci]). Within our uncertainty limits we detect no anisotropy for
the electron effective mass, which is consistent with most previous theoretical
calculations. We discuss upper limits for possible anisotropy of the electron
effective mass parameter from our experimental uncertainty limits, and we
compare our findings with recent theoretical results
Electron Entanglement via a Quantum Dot
This Letter presents a method of electron entanglement generation. The system
under consideration is a single-level quantum dot with one input and two output
leads. The leads are arranged such that the dot is empty, single electron
tunneling is suppressed by energy conservation, and two-electron virtual
co-tunneling is allowed. This yields a pure, non-local spin-singlet state at
the output leads. Coulomb interaction is the nonlinearity essential for
entanglement generation, and, in its absence, the singlet state vanishes. This
type of electron entanglement is a four-wave mixing process analogous to the
photon entanglement generated by a Chi-3 parametric amplifier.Comment: 4 page
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