Exchange energy in coupled quantum dots

Abstract

In this work, the exchange energy J for a system of two laterally-coupled quantum dots, each one with an electron, is calculated analytically and in a detailed form, considering them as hydrogen-like atoms, under the Heitler-London approach. The atomic orbitals, associated to each quantum dot, are obtained from translation relations, as functions of the Fock-Darwin states. Our results agree with the reported ones by Burkard, Loss and DiVincenzo in their model of quantum gates based on quantum dots, as well as with some recent experimental reports.

Energy Levels in a Single-Electron Quantum Dot with Hydrostatic Pressure

“…This is the result of increase of the magnetic field B for a pressure P = 0. The results are in agreement with the results of Caicedo-Ortiz et al [7]. As the magnetic field changes over the quantum dot, the energy levels intersect.…”

“…Semiconductor quantum dots (QDs) are lowdimensional systems, in which charge carriers are confined to three dimensions [1][2][3][4][5][6][7], and are composed mainly of GaAs, GaAsAl, CdSe, or PbS. The quantum dot acts as a box that confines particles like electrons, holes or excitons, where the number of particles is controlled by applying a potential difference across two electrodes connected to the system.…”

“…Previous work has been done on the effects of hydrostatic pressure on the energy behavior of quantum dots with multiple electrons, with the use of different geometries [8][9][10][11][12][13][14][15][16][17][18][19]. Photoluminescence measurement under high hydrostatic pressure has proven to be a useful tool for exploring the electronic structure and optical transitions in quantum dots [20,21].…”

“…Burkard et al [30] considered a quantum-gate mechanism based on electron spins in coupled semiconductor quantum dots. Caicedo-Ortiz et al [31] proposed a scheme switching system for two laterally coupled quantum dots operating as a quantum gate 2-qubits. A study of the short time dynamics of a charge qubit encoded in two coherently coupled quantum dots connected to external electrodes has also been studied by Łuczak and Bułka [32].…”

A configuration interaction analysis of exchange in double quantum dots

“…Lastly, we compare the CI method with Heitler London (HL) and Hund Mulliken (HM) techniques which previous studies [17][18][19][20][21][22][23] use to study DQD exchange energy. The CI outlined here is more general than these methods from a variational standpoint: The full CI is a variational method and the space of trial wavefunctions includes the HL and HM spaces as long as the number of Gaussian functions n G ≥ 2 (and is identical to HM for n G = 2).…”