21 research outputs found
Effect of Pavement Stiffness on the Shape of Deflection Bowl
The paper introduces a new method for calculating the elastic moduli of pavement layers.
The method requires only two input par
ameters: the thickness of the upper „bound” layer and the
Falling Weight Deflectometer (FWD) or Improved Benkelman Beam Apparatus (IBBA) measurement
data. The authors developed a continuously differentiable regression function, which can be applied to
desc
ribe the shape of the deflection bowl. Additional parameters of the deflection bowl (e.g. radius of
curvature, position of inflexion point) can be calculated based on the regression function. FWD
measurements were simulated running the BISAR (Bitumen Stres
s Analysis in Roads) software on
different pavement variations. Outputs of the simulations were further processed with self
-
developed
software. As a result, a series of diagrams were elaborated, by which the elastic moduli of the
pavement layers can be det
ermined
Intraband electron focusing in bilayer graphene
We propose an implementation of a valley selective electronic Veselago lens
in bilayer graphene. We demonstrate that in the presence of an appropriately
oriented potential step, low-energy electrons radiating from a point source can
be re-focused coherently within the same band. The phenomenon is due to the
trigonal warping of the band structure that leads to a negative refraction
index. We show that the interference pattern can be controlled by an external
mechanical strain.Comment: 14 pages, 8 figure
Thermoelectric Performance of various Benzo-difuran Wires
Using a first principles approach to electron transport, we calculate the
electrical and thermoelectrical transport properties of a series of molecular
wires containing benzo-difuran subunits. We demonstrate that the side groups
introduce Fano resonances, the energy of which is changing with the
electronegativity of selected atoms in it. We also study the relative effect of
single, double or triple bonds along the molecular backbone and find that
single bonds yield the highest thermopower, approximately 22V/K at room
temperature, which is comparable with the highest measured values for
single-molecule thermopower reported to date.Comment: 7 pages, 8 figure
Twist angle controlled collinear Edelstein effect in van der Waals heterostructures
The generation of spatially homogeneous spin polarization by application of electric current is a fundamental manifestation of symmetry-breaking spin-orbit coupling (SOC) in solid-state systems, which underpins a wide range of spintronic applications. Here, we show theoretically that twisted van der Waals heterostructures with proximity-induced SOC are candidates par excellence to realize exotic spin-charge transport phenomena due to their highly tunable momentum-space spin textures. Specifically, we predict that graphene/group-VI dichalcogenide bilayers support room temperature spin-current responses that can be manipulated via twist-angle control. For critical twist angles, the nonequilibrium spin density is pinned parallel to the applied current. This effect is robust against twist-angle disorder, with graphene/WSe2 possessing a critical angle (purely collinear response) of θc≃14°. A simple electrical detection scheme to isolate the collinear Edelstein effect is proposed
Two-dimensional electron scattering in regions of nonuniform spin-orbit coupling
We present a theoretical study of elastic spin-dependent electron scattering
caused by a nonuniform Rashba spin-orbit coupling strength. Using the
spin-generalized method of partial waves the scattering amplitude is exactly
derived for the case of a circular shape of scattering region. We found that
the polarization of the scattered waves are strongly anisotropic functions of
the scattering angle. This feature can be utilized to design a good
all-electric spin-polarizer. General properties of the scattering process are
also investigated in the high and low energy limits.Comment: 4 pages, 3 figure
Boundary conditions for transition-metal dichalcogenide monolayers in the continuum model
We derive the boundary conditions for MoS2 and similar transition-metal dichalcogenide hon- eycomb (2H polytype) monolayers with the same type of k ·p Hamiltonian within the continuum model around the K points. In an effective 2-band description, the electron–hole symmetry break- ing quadratic terms are also taken into account. We model the effect of the edges with a linear edge constraint method that has been applied previously to graphene. Focusing mainly on zigzag edges, we find that different reconstruction geometries with different edge-atoms can generally be described with one scalar parameter varying between 0 and 2π. We analyze the edge states and their dispersion relation in MoS2 in particular, and we find good agreement with the results of previous density functional theory calculations for various edge types
Theory of valley-resolved spectroscopy of a Si triple quantum dot coupled to a microwave resonator
We theoretically study a silicon triple quantum dot (TQD) system coupled to a superconducting microwave resonator. The response signal of an injected probe signal can be used to extract information about the level structure by measuring the transmission and phase shift of the output field. This information can further be used to gain knowledge about the valley splittings and valley phases in the individual dots. Since relevant valley states are typically split by several , a finite temperature or an applied external bias voltage is required to populate energetically excited states. The theoretical methods in this paper include a capacitor model to fit experimental charging energies, an extended Hubbard model to describe the tunneling dynamics, a rate equation model to find the occupation probabilities, and an input–output model to determine the response signal of the resonator.publishe