MAGNETIC AND ELECTRONIC PROPERTIES OF InAs ANISOTROPIC DOPED QUANTUM DOT WITH SPIN-ORBIT COUPLING: COMPUTATIONAL STUDY
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Date
2023-05-15
Authors
Ayham Anwar Ahmad Shaer
Journal Title
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Publisher
An - Najah National University
Abstract
The anisotropic quantum dot (QD) Hamiltonian has been solved using the diagonalization method in the presence of a perpendicular magnetic field and Gaussian impurity, considering both types of spin-orbit interaction (SOI): Rashba and Dresselhaus. The diagonalization process has been carried out using the one-dimensional harmonic oscillator basis.
The acceptor impurity's presence significantly affects the system's eigensolution, specifically causing an interesting level crossing between the states and changing the ground state order. Furthermore, the impurity's strength, position, and spatial stretch have been investigated, and the result shows that the impurity plays an important role in manipulating the QD properties.
The magnetization and magnetic susceptibility as important quantities of the QD system made from InAs are studied. The results show a diamagnetic-paramagnetic phase transition at low temperatures due to the impurity presence. This magnetic transition strongly correlates with the impurity profiles (strength, position, and influence domain), magnetic field, and temperature. As the strength of the impurity increases, the diamagnetic-paramagnetic transition occurs at a lower value of the magnetic field.
In addition, the effective Lande factor g of the system has been studied. The result shows that, as the electric field increases, the Rashba SOI increases |g|, while the Dresselhaus SOI reduced |g| of the QD. Furthermore, in the presence of both types of SOI, increasing the electric field enhances the |g| since in the InAs material, the Rashba SOI dominates the Dresselhaus SOI. The result emphasizes the role of Rashba SOI in spintronics devices.
The confinement strength effect on the g has been investigated, the g shows a peak value at particular confinement strength. In addition, the anisotropy of the QD shows a significant role in controlling g.
The density of states of the system has also been computed to physically describe the impact of each system parameter on the energy spectrum. As the magnetic field turns on, the figures demonstrate how the anisotropy of the confinement potential also causes the harmonic oscillator symmetry to be broken.