2,531 research outputs found
Gap opening in graphene by simple periodic inhomogeneous strain
Using ab-initio methods, we show that the uniform deformation either leaves
graphene (semi)metallic or opens up a small gap yet only beyond the mechanical
breaking point of the graphene, contrary to claims in the literature based on
tight-binding (TB) calculations. It is possible, however, to open up a global
gap by a sine-like one-dimensional inhomogeneous deformation applied along any
direction but the armchair one, with the largest gap for the corrugation along
the zigzag direction (~0.5 eV) without any electrostatic gating. The gap
opening has a threshold character with very sharp rise when the ratio of the
amplitude A and the period of the sine wave deformation lambda exceeds
(A/lambda)_c ~0.1 and the inversion symmetry is preserved, while it is
threshold-less when the symmetry is broken, in contrast with TB-derived
pseudo-magnetic field models.Comment: 6 pages, 6 figures; (v2) added figures illustrating opening gap in
Graphene mesh on BN, expanded analysis illustrating absence of
pseudo-magnetic fields in deformed Graphen
Neutrino-nucleon cross sections at energies of Megaton-scale detectors
An updated set of (anti)neutrino-nucleon charged and neutral current cross
sections at is presented.
These cross sections are of particular interest for the detector optimization
and data processing and interpretation in the future Megaton-scale experiments
like PINGU, ORCA, and Hyper-Kamiokande. Finite masses of charged leptons and
target mass corrections in exclusive and deep inelastic
interactions are taken into account. A new set of QCD NNLO parton density
functions, the ABMP15, is used for calculation of the DIS cross sections. The
sensitivity of the cross sections to phenomenological parameters and to
extrapolations of the nucleon structure functions to small and is
studied. An agreement within the uncertainties of our calculations with
experimental data is demonstrated.Comment: 4 pages, 4 figures, accepted for the VLVnT-2015 Conference
proceedings, will be published on EPJ Web of Conference
The Paths of Unification In The GUST With The G x G Gauge Groups of E(8) x E(8)
In the framework of the four dimensional heterotic superstring with free
fermions we discuss the rank eight and/or sixteen Grand Unified String Theories
(GUST) which contain the SU(3)_H - gauge family symmetry. We explicitly
investigate the paths of the unification in the GUST with gauge symmetry G x G
= [SU(5) x U(1) x (SU(3) x U(1))_H]^2. We show that the GUSTs with the G x G
gauge group allow to make the scale of unification to be consistent with the
string scale M_SU = g_{string} * 5 * 10^17 GeV.Comment: 18 pages, 2 Postscript figures, uses epsf.st
Two- and Three-particle States in a Nonrelativistic Four-fermion Model in the Fine-tuning Renormalization Scheme. Goldstone mode "against" extension theory
In a nonrelativistic contact four-fermion model we show that simple
regularisation prescriptions together with a definite fine-tuning of the
cut-off-parameter dependence of ``bare'' quantities give the exact solutions
for the two-particle sector and Goldstone modes. Their correspondence with the
self-adjoint extension into Pontryagin space is established leading to
self-adjoint semi-bounded Hamiltonians in three-particle sectors as well.
Renormalized Faddeev equations for the bound states with Fredholm properties
are obtained and analysed.Comment: 23 pages, LaTeX, changed content, added references and two figures,
to appear in the Few Body System
Electric Current and Noise in Long GaN Nanowires in the Space-Charge Limited Transport Regime
We studied electric current and noise in planar GaN nanowires (NWs). The
results obtained at low voltages provide us with estimates of the depletion
effects in the NWs. For larger voltages, we observed the space-charge limited
current (SCLC) effect. The onset of the effect clearly correlates with the NW
width. For narrow NWs the mature SCLC regime was achieved. This effect has
great impact on fluctuation characteristics of studied NWs. At low voltages, we
found that the normalized noise level increases with decreasing NW width. In
the SCLC regime, a further increase in the normalized noise intensity (up to
1E4 times) was observed, as well as a change in the shape of the spectra with a
tendency towards slope -3/2. We suggest that the features of the electric
current and noise found in the NWs are of a general character and will have an
impact on the development of NW-based devices.Comment: 12 pages, 4 figures in Fluctuation and Noise Letters (2017
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