Interplay of fractional quantum Hall states and localization in quantum point contacts
| Autor: | Thomas Ihn, Klaus Ensslin, P.-L. Ardelt, Christian Reichl, Clemens Rössler, E. de Wiljes, Stephan Baer, Werner Wegscheider |
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| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Physics
Condensed matter physics Condensed Matter - Mesoscale and Nanoscale Physics FOS: Physical sciences Heterojunction Electron Quantum Hall effect Condensed Matter Physics Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Electronic Optical and Magnetic Materials Magnetic field Quantum spin Hall effect Quantum mechanics Mesoscale and Nanoscale Physics (cond-mat.mes-hall) Quasiparticle Quantum Quantum tunnelling |
| Popis: | We investigate integer and fractional quantum Hall states in quantum point contacts (QPCs) of different geometries, defined in AlGaAs/GaAs heterostructures employing different doping and screening techniques. We find that, even in the highest mobility samples, interference and localization strongly influence the transport properties. We propose microscopic models for these effects, based on single- and many-electron physics. For integer quantum Hall states, transport is modulated due to the self-consistent formation of compressible regions of enhanced or reduced density in the incompressible region of the constriction. In the fractional quantum Hall regime, we observe the localization of fractionally charged quasi-particles in the constriction and an interplay of single- and many-electron physics. At low electron densities and in comparatively weak magnetic fields, single-electron interference dominates transport. Utilizing optimized growth and gating techniques, the $\nu$=5/2 state can be observed in a QPC, conserving the bulk properties in an unprecedented quality. Our results might improve the understanding of the influence of localization on the transmission properties of QPCs, which is necessary for the interpretation of interference experiments employing QPCs, especially at $\nu$=5/2. Comment: 16 pages, 7 figures |
| Databáze: | OpenAIRE |
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