Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Electrons in artificial atomsReview paper by R. C. AshooriNature, VOL 379, 1996Review by Qin ZhouQuantum dots—artificial atoms•Quantum dots are so small that they can contain just one mobile electron.•By varying controllably the number of electrons in these ‘artificial atoms’ and measuring the energy required to add successive electrons, one can conduct atomic physics experiments in regime that is inaccessible to experiments on real atoms.Single-electron capacitance spectroscopy (SECS)•Quantum dot between two capacitor plates•Close to bottom plate to allow tunneling•Realize: •10nm AlGaAs (insulator)•10nm GaAs (Quantum well)• Gate (Confine electrons laterly)•Apply voltage on gate to attract electronsSingle-electron capacitance spectroscopy (SECS)‘Gated transport spectroscopy’ (GTS)•Similar Principle•About 30 electrons in the dot•Can operate in DC modeArtificial atom model•n – radial quantum number•l – angular quantum number, 0(2 1)n lE n lw= + +h2 2, 0[ / 2 ( / 2) (2 1)]n l c cE l n lhw h w w= + + + +Highest energy electron may be in a different quantum level depending on the magnetic field, and each of these levels has a different evolution in magnetic field.Similar experiments•Uri Banin, et al., Nature, VOL 400, 1999Thank you!The
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