Exchange interaction and stability diagram of coupled quantu

The charge stability diagram for two coupled quantum dots containing up to two electrons is computed in magnetic fields. One- and two-particle Schroedinger equations are solved by exact diagonalization to obtain the chemical potentials and exchange energy

ExchangeinteractionandstabilitydiagramofcoupledquantumarXiv:cond-mat/0607571v1 [cond-mat.mes-hall] 22 Jul 2006dotsinmagnetic eldsL.-X.Zhang,D.V.Melnikov,andJ.-P.LeburtonBeckmanInstituteforAdvancedScience&TechnologyandDepartmentofElectricalandComputerEngineering,UniversityofIllinoisatUrbana-Champaign,Urbana,Illinois61801(Dated:February6,2008)AbstractThechargestabilitydiagramfortwocoupledquantumdotscontaininguptotwoelectronsiscomputedinmagnetic elds.One-andtwo-particleSchr¨odingerequationsaresolvedbyexactdiagonalizationtoobtainthechemicalpotentialsandexchangeenergyinthesesystems.Byan-alyzingthechemicalpotentialsvariationwithexternalbiasesandmagnetic elds,itispossibletodistinguishbetweentheweakandstronginter-dotcouplings.Thevariationofthechemicalpotentialcurvaturesandthedouble-triplepointseparationsinthestabilitydiagramscon rmstheinter-dotcouplingdecreasewithincreasingmagnetic elds.Thecomputedexchangeenergiesarealsofoundtobesigni cantlysmallerthanthevaluesestimatedfromthestabilitydiagram.PACSnumbers:,73.21.-b