Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userCoulomb and tunneling coupled trilayer systems at zero magnetic field
55
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
The ground-state electronic configuration of three coupled bidimensional electron gases has been determined using a variational Hartree-Fock approach, at zero magnetic field. The layers are Coulomb coupled, and tunneling is present between neighboring layers. In the limit of small separation between layers, the tunneling becomes the dominant energy contribution, while for large distance between layers the physics is driven by the Hartree electrostatic energy. Transition from tunneling to hartree dominated physics is shifted towards larger layer separation values as the total bidimensional density of the trilayers decreases. The inter-layer exchange helps in stabilize a balanced configuration, where the three layers are approximately equally occupied; most of the experiments are performed in the vicinity of this balanced configuration. Several ground-state configurations are consequence of a delicate interplay between tunneling and inter-subband exchange.
rate research
Read More
We have studied the tunneling properties of GaSb/AlSb/InAs/AlSb/GaSb heterostructures, in which electrons and holes accumulate in the InAs and GaSb regions respectively, under a magnetic field parallel to the interfaces. The low-temperature (T = 4.2K), zero-bias magnetoconductance has shown a behavior with field that evidences the two-dimensional character of both electrons and holes and that has allowed us to determine the hole density and the electron-hole separation. The observed field dependence of the current-voltage characteristics is explained by the relative change in parallel momentum of electrons and holes induced by the field.
The electron tunneling is experimentally studied between two-dimensional electron gases (2DEGs) formed in a single-doped-barrier heterostructure in the magnetic fields directed perpendicular to the 2DEGs planes. It is well known that the quantizing magnetic field induces the Coulomb pseudogap suppressing the electron tunneling at Fermi level. In this paper we firstly present the experimental results revealing the pseudogap in the electron tunneling assisted by elastic electron scattering on disorder.
Ballistic electron transport is a key requirement for existence of a topological phase transition in proximitized InSb nanowires. However, measurements of quantized conductance as direct evidence of ballistic transport have so far been obscured due to the increased chance of backscattering in one dimensional nanowires. We show that by improving the nanowire-metal interface as well as the dielectric environment we can consistently achieve conductance quantization at zero magnetic field. Additionally, studying the sub-band evolution in a rotating magnetic field reveals an orbital degeneracy between the second and third sub-bands for perpendicular fields above 1T.
We calculate the plasmon dispersion relation for Coulomb coupled metallic armchair graphene nanoribbons and doped monolayer graphene. The crossing of the plasmon curves, which occurs for uncoupled 1D and 2D systems, is split by the interlayer Coulomb coupling into a lower and an upper plasmon branch. The upper branch exhibits a highly unusual behavior with endpoints at finite $q$. Accordingly, the structure factor shows either a single or a double peak behavior, depending on the plasmon wavelength. The new plasmon structure is relevant to recent experiments, its properties can be controlled by varying the system parameters, and be used in plasmonic applications.
The ability to convert spin accumulation to charge currents is essential for applications in spintronics. In semiconductors, spin-to-charge conversion is typically achieved using the inverse spin Hall effect or using a large magnetic field. Here we demonstrate a general method that exploits the non-linear interactions between spin and charge currents to perform all-electrical, rapid and non-invasive detection of spin accumulation without the need for a magnetic field. We demonstrate the operation of this technique with ballistic GaAs holes as a model system with strong spin-orbit coupling, in which a quantum point contact provides the non-linear energy filter. This approach is generally applicable to electron and hole systems with strong spin orbit coupling.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
