12,436 research outputs found
Impact of built-in fields and contact configuration on the characteristics of ultra-thin GaAs solar cells
We discuss the effects of built-in fields and contact configuration on the
photovoltaic characteristics of ultrathin GaAs solar cells. The investigation
is based on advanced quantum-kinetic simulations reaching beyond the standard
semi-classical bulk picture concerning the consideration of charge carrier
states and dynamics in complex potential profiles. The thickness dependence of
dark and photocurrent in the ultra-scaled regime is related to the
corresponding variation of both, the built-in electric fields and associated
modification of the density of states, and the optical intensity in the films.
Losses in open-circuit voltage and short-circuit current due to leakage of
electronically and optically injected carriers at minority carrier contacts are
investigated for different contact configurations including electron and hole
blocking barrier layers. The microscopic picture of leakage currents is
connected to the effect of finite surface recombination velocities in the
semi-classical description, and the impact of these non-classical contact
regions on carrier generation and extraction is analyzed.Comment: 5 pages, 8 figure
LMI based Stability and Stabilization of Second-order Linear Repetitive Processes
This paper develops new results on the stability and control of a class of linear repetitive processes described by a second-order matrix discrete or differential equation. These are developed by transformation of the secondorder dynamics to those of an equivalent first-order descriptor state-space model, thus avoiding the need to invert a possibly ill-conditioned leading coefficient matrix in the original model
Supersymmetric analogue of BC_N type rational integrable models with polarized spin reversal operators
We derive the exact spectra as well as partition functions for a class of
type of spin Calogero models, whose Hamiltonians are constructed by
using supersymmetric analogues of polarized spin reversal operators (SAPSRO).
The strong coupling limit of these spin Calogero models yields type of
Polychronakos-Frahm (PF) spin chains with SAPSRO. By applying the freezing
trick, we obtain an exact expression for the partition functions of such PF
spin chains. We also derive a formula which expresses the partition function of
any type of PF spin chain with SAPSRO in terms of partition functions of
several type of supersymmetric PF spin chains, where .
Subsequently we show that an extended boson-fermion duality relation is obeyed
by the partition functions of the type of PF chains with SAPSRO. Some
spectral properties of these spin chains, like level density distribution and
nearest neighbour spacing distribution, are also studied.Comment: 36 pages, 2 figures. arXiv admin note: text overlap with
arXiv:1402.275
Relevance of Induced Gauge Interactions in Decoherence
Decoherence in quantum cosmology is shown to occur naturally in the presence
of induced geometric gauge interactions associated with particle production.A
new 'gauge '-variant form of the semiclassical Einstein equations is also
presented which makes the non-gravitating character of the vacuum polarisation
energy explicit.Comment: 10 pages, LATEX, IC/94/16
Rapidly rotating strange stars for a new equation of state of strange quark matter
For a new equation of state of strange quark matter, we construct equilibrium
sequences of rapidly rotating strange stars in general relativity. The
sequences are the normal and supramassive evolutionary sequences of constant
rest mass. We also calculate equilibrium sequences for a constant value of
corresponding to the most rapidly rotating pulsar PSR 1937 + 21. In
addition to this, we calculate the radius of the marginally stable orbit and
its dependence on , relevant for modeling of kilo-Hertz quasi-periodic
oscillations in X-ray binaries.Comment: Two figures, uses psbox.tex and emulateapj5.st
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