arXiv subjects

Abdellatif Kamal

Publications and source records attributed to Abdellatif Kamal.

14 recordsLinked to original sources

arXiv2024

Dirac fermions collimation in heterostructures based on tilted Dirac cone materials

This paper aims to theoretically analyze the behavior of Dirac fermions in tilted Dirac cone material, particularly those that have diffused a barrier potential.Our results show that the degree of tilt in the y-direction can lead to different collimations of the Dirac fermion beams relative to the Fermi and confinement surfaces. To study the transmission probability, we exploited our results numerically, taking into account the various configurations of the system and the different external and internal physical parameters by characterizing the behavior of fermionic transport in a proposed heterostructure. Our findings lay the groundwork for developing controllable electronic devices utilizing Dirac fermion collimation, governed by the tilt parameter, enabling precise manipulation and enhanced functionality.

cond-mat.mes-hall↗

arXiv2022

Quantum teleportation via a two-qubit Heisenberg XXX chain with x-component of Dzyaloshinskii-Moriya interaction

In this paper, we investigate the thermal entanglement and teleportation of a thermally mixed entangled via a two-qubit Heisenberg XXX chain with the x-component $D_x$ of the Dzyaloshinskii-Moriya interaction. Our findings suggest that temperature $T$, spin coupling constant J, and the x-components $D_x$ may influence entanglement of the output states and, consequently, the possibilities of teleportation protocols. Furthermore, these results indicate that the entanglement of the output states requires a low-temperature regime, weak Dzyaloshinskii-Moriya interaction, or an antiferromagnetic chain. Finally, the channel becomes entangled, making the teleportation protocol conceivable and feasible.

quant-ph↗

arXiv2022

Entanglement in a two-qubit Heisenberg XXX chain with x-components of Dzyaloshinskii-Moriya and Kaplan-Shekhtman-Entin-Wohlman-Aharony interactions

This article explores the concurrence, including entanglement, in a two-qubit Heisenberg XXX chain with Dzyaloshinskii-Moriya and Kaplan-Shekhtman-Entin-Wohlman-Aharony interactions. The concurrence expression was developed using the physical variables connected with the chosen system. Our results indicate that temperature, the spin coupling constant $J$, the x-components $D_x$, and $Γ_x$ may all play a role in determining the degree of intricacy between states. Additionally, these findings imply that the separability of states is possible for high-temperature domains or ferromagnetic chains. In contrast, the entanglement of states may be achieved by using high values for the x-components $D_x$ or $Γ_x$ parameters or by using an antiferromagnetic chain.

quant-ph↗

arXiv2022

Electron flow in Monolayer Molybdenum Disulfide Quantum Dot with Magnetic Flux

We study the Dirac electron scattering problem on a potential barrier in a circular quantum dot of Monolayer Molybdenum Disulfide quantum dot MoS2 subjected to magnetic flux. By solving Dirac's equation, we formulate analytical expressions for the eigenstates, scattering coefficients, scattering efficiency, and the reflected current's radial component. We show that the scattering coefficients, the scattering efficiency, and the radial component of the reflected current depend explicitly on the magnetic flux. The magnetic flux may cause a slight shift in the oscillation position of the scattering coefficients. For scattering efficiency, magnetic flux may also lead to a slight shift in their oscillation position and an increase in amplitude when the magnetic flux decreases.

cond-mat.mes-hall↗

arXiv2021

Local quantum uncertainty of two gravitational cat states in inhomogeneous magnetic field

This paper investigates the local quantum correlations (LQU), including entanglement, of two gravitational cat states subjected to an inhomogeneous magnetic field. We derived the LQU expression from the physical quantities associated with the selected system. Our findings suggest that temperature, magnetic field, and magnetic field inhomogeneity may all play a role in determining the degree of intricacy between the gravcats to some extent. Furthermore, these conclusions suggest that the thermal LQU captures a stronger quantum correlation than the entanglement. Especially true for low external magnetic field levels combined with low field inhomogeneity or high-temperature domains. Besides, we obtained the states' separability for large values of field inhomogeneity. Moreover, the correlation of the states obtained is maximal for small magnetic field values at low temperatures. Finally, we note that the state's systems become non-entangled and separable when the gap between the fundamental level and the first excited level becomes large.

quant-ph↗

arXiv2021

The correlation function of a two-dimensional electron gas with anharmonic potential and Rashba coupling

In this paper, we study a two-dimensional gas of electrons with Rashba spin-orbit coupling with anharmonic potential. The splitting of the Hamiltonian in two parts can be recovering the Jaynes-Cummings model, which describes a system with two states. The dynamics of the rising Pauli operator and the creation operators are studied. Finally, we examined the behavior of the correlation function of emission and absorption photons for the strong and weak coupling.

cond-mat.mes-hall↗

arXiv2021

Energy levels of monolayer -- AA-stacked bilayer graphene quantum dots

This work investigates the electronic properties of the energy spectrum of a hybrid system composed of (i) a circular quantum dot of monolayer graphene surrounded by an infinite sheet of AA-stacked bilayer graphene and (ii) a circular quantum dot of AA-stacked graphene bilayer surrounded by infinite monolayer graphene. We establish analytical findings for the related energy levels and wave functions using the continuum model and the zigzag boundary conditions at the graphene monolayer-bilayer interface. We investigate the effects of perpendicular magnetic, dot radius, and electrical fields on the two types of hybrid system quantum dots. We compare our results to previously published work and explore the potential uses of such a hybrid system quantum dot.

cond-mat.mes-hall↗

arXiv2021

Thermodynamic Properties of $q-$deformed massless Dirac fermions in graphene with Rashba coupling

We study the thermodynamic properties of massless Dirac fermions in graphene under a uniform magnetic field and Rashba spin-orbit coupling with a $q-$deformed Heisenberg algebra calculus. The thermodynamic functions such as the Helmholtz free energy, total energy, entropy and heat capacity are obtained by using an approach based on the zeta function and Euler-Maclaurain formula. These functions will be numerically examined for different values of $η={1\over i}\ln(q)$. In particular, the heat capacity in the presence of deformation, all curves coincide and reach the fixed value $C=6K_B$ three times greater compared to the case of undeformed massless Dirac fermions in graphene.

hep-th↗

arXiv2021

Scattering in Monolayer Molybdenum Disulfide Quantum Dot

We investigate the propagation of electrons in a circular quantum dot of monolayer Molybdenium disulfide MoS_2, subjected to an electric potential. Using the continuum model, we present analytical expressions for the eigenstates, scattering coefficients, scattering efficiency, and radial component of the reflected current and electron density. We identify two scattering regimes as a function of physical parameters such as incident electronic energy, potential barrier, and quantum dot radius. For the incident electron low energy, we show that there is an appearance of scattering resonances. Also, we note that the Far-field scattered current has distinct preferred scattering directions.

cond-mat.mes-hall↗

arXiv2020

Zitterbewegung Effect in Graphene with Spacially Modulated Potential

The Zitterbewegung (ZB) effect is investigated in graphene with spacially modulated potential near the original Dirac point (ODP) and extra Dirac points (EDPs). Our calculations show that to get the large ZB oscillations, the wave packet center must be at the angle $θ_0=0$ for EDPs located at zero-energy, or $θ_0=π/2$ for both ODP and EDPs at finite energy $\varepsilon=mπ$ ($m$ integer). By varying the parameters ($q_2, \mathbb{V}$) of the periodic potential and the initial momentum ($κ_0, θ_0$) of Gaussian wave packet, it is found that the frequency of the ZB oscillations is in the range $[10^{7}~\text{Hz}, 10^{13}~\text{Hz}$] depending on what type of EDP is generated and the amplitude reaches hundreds of angstroms but their attenuation becomes very slow. More analysis of the frequency shows the possibilities in experimentally realizing the ZB effect in our system.

cond-mat.mes-hall↗

arXiv2019

Goos-Hänchen Shifts in Graphene with Spatially Modulated Potential

Using the energy spectrum of graphene with spatially modulated potential, we study the Goos-Hänshen shifts near extra Dirac points located at finite energy $\varepsilon=mπ$, with $m$ integer. On both sides of such points, we show that the Goos-Hänshen shifts can be negative as well as positive under various conditions. It is found that the shifts are strongly depending on the effects of the incident energy, potential height, incident angle and width of central region of unit cell. Such effects tell us that such width can be used to tune the shifts at the extra Dirac points.

cond-mat.mes-hall↗

arXiv2019

Electronic Structure of Graphene with two Strains and Double Barrier

We study the electronic structure of Dirac fermions scattered by double barrier potential in graphene under strain effect. We show that traction and compression strains can be used to generate fermion beam collimation, 1D channels, surface states and confinement. The corresponding transmission probability and conductance at zero temperature are calculated and their numerical implementations taking into account different configurations of physical parameters enabled us to analyze some features of the system.

cond-mat.mes-hall↗

arXiv2018

Transport Properties in Graphene Superlattices

Using Chebyshev polynomials, we study the electronic transport properties of massless Dirac fermions in symmetrical graphene superlattice composed of three regions. Matching wavefunctions and using transfer matrix method, we explicitly determine transmission probability as well as the conductance and Fano factor. At vertical Dirac points, we numerically find that the transmission probability shows transmission gaps, conductance has minimums and Fano factor has maximums.

cond-mat.mes-hall↗

arXiv2017

Band Structures of Symmetrical Graphene Superlattice with Cells of three Regions

We study the electronic band structures of massless Dirac fermions in symmetrical graphene superlattice with cells of three regions. Using the transfer matrix method, we explicitly determine the dispersion relation in terms of different physical parameters. We numerically analyze such relation and show that there exist three zones: bound, unbound and forbidden states. In the central zone of the band structures, we determine and enumerate the vertical Dirac points, opening gaps and additional Dirac points. Finally, we inspect the potential effect on minibands, the anisotropy of group velocity and the energy bands contours near Dirac points. We also discuss the evolution of gap edges and cutoff region near the vertical Dirac points.

cond-mat.mes-hall↗