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Probing electron-electron interactions with a quantum antidot

In the integer quantum Hall (IQH) regime, an antidot provides a finite, controllable ‘edge’ of quantum Hall fluid which is an ideal laboratory for investigating the collective dynamics of large numbers of interacting electrons. Transport measurements of single antidotes probe the orbital energy spectra of the antidot edge, and gate-defined antidot devices offer the flexibility to vary both the dimensions of the antidot and the couplings to the extended IQH edge modes which serve as leads. We can also use the spin-selectivity of the IQH edge modes to perform spin-resolved transport measurements, from which we can infer the antidot spin-structure. This thesis describes a combination of such experimental measurements and related computational models designed to investigate the effects of electron-electron interactions in quantum antidotes, with general implications for the physics of spin and charge in IQH systems. Our work provides a powerful example of the practical applications of IQH edge modes for selective transport in mesoscopic quantum electronics, which we have used to perform the first spin-resolved measurements of V<sub>AD </sub>= 2 transmission resonances. Our discovery of spin-charge separation in the low-field antidot excitation spectrum paints a picture of the antidot as a finite droplet of interacting IQH fluid in the LLL, with all of the rich physics of exchange, collective modes, spin textures, etc., which this entails. Our results are therefore relevant not only for the physics of antidots, but more broadly for the understanding of interacting electronic systems of many particles in the IQH regime.
Date January 2009
CreatorsBassett, L. C.
PublisherUniversity of Cambridge
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation

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