Study On Properties Of Two-Electron In Triple Quantum Dots Under Magnetic Fields

In the past dozens of years, with the development of nanotechnology and preparation technology of semiconductor superlattices, many people have already paid attention to the quantum dot. Nowadays, many kinds of technologies are applied to prepare various scales of quantum dots. With a great deal of theoretical calculation and experimental study, many peculiar physical phenomena have been proposed in quantum dots, i.e., tunneling phenomenon, coulomb blockade, quantum entanglement and correlation. These properties can be applied to the design of quantum devices and quantum computer, etc.In this paper, we consider properties of two-electron in triple quantum dots under magnetic fields. Under effective-mass theory, using two-dimensional grid finite difference method, we calculate correlated energy, ground state level and wave function distribution, which affected by the intensity of magnetic field, the size and shape of the quantum dot. We compare the results with the single quantum dot.Two electrons appear separation with the increasing scale of the single quantum dot. Because of the strong coulomb repulsion, average spacing of two electrons increases, at the same time, electron-electron correlation enhances and correlated energy increases. When the quantum dot is large enough, electrons can be localized in different positions, and Wigner molecule is created. Our results are consistent with the existing research results. We also prove the method we adopt is correct.Based on this, the properties of two electrons in triple quantum dots have been studied. Triple quantum dots system is more complicated. The distribution of wave functions are effected by triple quantum dot scale: When triple quantum dots are small, two electrons are in the middle quantum well with larger probability; when triple quantum dots are large, electrons are localized on both sides of the quantum wells. Two quantum dots are coupled by tunneling with two barriers. With the increase of barrier thickness, two electrons separate further which leads to stronger correlation and larger correlated energy. Effective interaction becomes small which make the ground state level reduce.Additionally, we propose the variation of properties with the width of potential wells. In the triple quantum dots, confinement effect on two electrons becomes weaker, which results from larger potential well width. For two electrons, the effective scale increases with the average spacing increases, the decreasing effective interaction causes the ground state level reduce. The calculation results of the single quantum dot and the triple quantum dots are the same for the quantum well of the sufficiently large size. As magnetic field intensity increases, confinement effect enhances and electrons are localized in a smaller range, correlation becomes weaker and ground state level increases. But the affect of magnetic field is not obvious.