Effects of Geometry on the Electronic Properties of Semiconductor Elliptical Quantum Rings

Abstract

The electronic states in GaAs-AlxGa1−xAs elliptically-shaped quantum rings are theoretically investigated through the numerical solution of the effective mass band equation via the finite element method. The results are obtained for different sizes and geometries, including the possibility of a number of hill-shaped deformations that play the role of either connected or isolated quantum dots (hills), depending on the configuration chosen. The quantum ring transversal section is assumed to exhibit three different geometrical symmetries - squared, triangular and parabolic. The behavior of the allowed confined states as functions of the cross-section shape, the ring dimensions, and the number of hills-like structures are discussed in detail. The effective energy bandgap (photoluminescence peak with electron-hole correlation) is reported as well, as a function of the Al molar fraction.

Shallow Donor Impurity States with Excitonic Contribution in GaAs/AlGaAs and CdTe/CdSe Truncated Conical Quantum Dots under Applied Magnetic Field

“…The wavefunctions and corresponding energies associated with Equation ( 2) have been obtained by implementing the FEM [52][53][54][55][56]. Within the COMSOL-Multiphysics licensed software [54][55][56], a user-controlled mesh was chosen in order to achieve greater control over discretization.…”

Down-conversion processes in ab-initio non-relativistic quantum electrodynamics

“…We can use this control, which is also experimentally realizable [25], to optimize the down-conversion process without breaking the symmetry of the matter subsystem. Finally, due to the rotational symmetry [25,48,49], a simple matteronly analysis would indicate that no (efficient) downconversion takes place. Due to the rotational symmetry of the eigenstates, only transitions that change the angular momentum by one (see also a detailed discussion in App.…”

Quantum particle motion on the surface of a helicoid in the presence of harmonic oscillator

“…Also, we are supposing we just have interest in the study of the dynamics of electrons on the surface S. Thus, we can imagine that the surface S corresponds to a given material with effective mass M 1 while the region perpendicular to S contains a different material with a different effective M 2 . An example of a study dealing with two different effective masses can be accessed in [51]. In addition, we can justify our interest in investigate anisotropic mass since some semiconductors materials, like Ge and Si, present ellipsoidal energy surfaces, related to different effective masses depending on the direction [52].…”