4,434 research outputs found
Non-adiabatic Current Excitation in Quantum Rings
We investigate the difference in the response of a one-dimensional
semiconductor quantum ring and a finite-width ring to a strong and short-lived
time-dependent perturbation in the THz regime. In both cases the persistent
current is modified through a nonadiabatic change of the many-electron states
of the system, but by different mechanisms in each case.Comment: LaTeX, 5 pages with 6 embedded postscript figures, submitted to 20th
Nordic Semiconductor Meeting, Tampere (2003
Third edge for a graphene nanoribbon: A tight-binding model calculation
The electronic and transport properties of an extended linear defect embedded
in a zigzag nanoribbon of realistic width are studied, within a tight binding
model approach. Our results suggest that such defect profoundly modify the
properties of the nanoribbon, introducing new conductance quantization values
and modifying the conductance quantization thresholds. The linear defect along
the nanoribbon behaves as an effective third edge of the system, which shows a
metallic behavior, giving rise to new conduction pathways that could be used in
nanoscale circuitry as a quantum wire.Comment: 6 pages, 6 figures. Two new figures and a few references adde
Carrier scattering, mobilities and electrostatic potential in mono-, bi- and tri-layer graphenes
The carrier density and temperature dependence of the Hall mobility in mono-,
bi- and tri-layer graphene has been systematically studied. We found that as
the carrier density increases, the mobility decreases for mono-layer graphene,
while it increases for bi-layer/tri-layer graphene. This can be explained by
the different density of states in mono-layer and bi-layer/tri-layer graphenes.
In mono-layer, the mobility also decreases with increasing temperature
primarily due to surface polar substrate phonon scattering. In
bi-layer/tri-layer graphene, on the other hand, the mobility increases with
temperature because the field of the substrate surface phonons is effectively
screened by the additional graphene layer(s) and the mobility is dominated by
Coulomb scattering.
We also find that the temperature dependence of the Hall coefficient in
mono-, bi- and tri-layer graphene can be explained by the formation of electron
and hole puddles in graphene. This model also explains the temperature
dependence of the minimum conductance of mono-, bi- and tri-layer graphene. The
electrostatic potential variations across the different graphene samples are
extracted.Comment: 18 pages, 7 figure
Model to Predict Duty of Community Nurses in Promotive and Preventive Care
Community nurses had important role in promotive and preventive care in community. Aim of the study was to make model to predict community nurses role in promotive and preventive care based on Health Promotion Model (HPM). Design of the study was used explanatory with cross sectional approach. Sum of participant was 161. This study was conducted in 11 Public Health Center in Banyuwangi at 1 January to 30 January 2018. Methods of data collection was cluster sampling. The data was analysed using smartPLS software.. Inner model: personal factors (t=1.981), interpersonal influences (t=4.036), situational influences (5.720), commitment (t=5.138) had affected to community nurses duty in promotive and preventive care. This model could predict community nurses duty in promotive and preventive care in high level (Q=0.998). That was important to enhance of community nurses duty through modifying commitment of nurses, interpersonal influence factors, personal factors and situational influence factors
Bulk and shear relaxation in glasses and highly viscous liquids
The ratio between the couplings of a relaxational process to compression and
shear, respectively, is calculated in the Eshelby picture of structural
rearrangements within a surrounding elastic matrix, assuming a constant density
of stable structures in distortion space. The result is compared to
experimental data for the low-temperature tunneling states in glasses and to
Prigogine-Defay data at the glass transition from the literature.Comment: 6 pages, 2 figures, 53 references; version after understanding the
Prigogine-Defay ratio at the glass transition in the accompanying paper
arXiv:1203.3555 [cond-mat.dis-nn
Nano-wires with surface disorder: Giant localization lengths and quantum-to-classical crossover
We investigate electronic quantum transport through nano-wires with one-sided
surface roughness. A magnetic field perpendicular to the scattering region is
shown to lead to exponentially diverging localization lengths in the
quantum-to-classical crossover regime. This effect can be quantitatively
accounted for by tunneling between the regular and the chaotic components of
the underlying mixed classical phase space.Comment: 4 pages, 3 figures; final version (including added references
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