Zusammenfassung
Two-dimensional semiconductor quantum dots are studied in the filling-factor range 2 <nu < 3. We find both theoretical and experimental evidence of a collective many-body phenomenon, where a fraction of the trapped electrons form an incompressible spin droplet on the highest occupied Landau level. The phenomenon occurs only when the number of electrons in the quantum dot is larger than similar to ...
Zusammenfassung
Two-dimensional semiconductor quantum dots are studied in the filling-factor range 2 <nu < 3. We find both theoretical and experimental evidence of a collective many-body phenomenon, where a fraction of the trapped electrons form an incompressible spin droplet on the highest occupied Landau level. The phenomenon occurs only when the number of electrons in the quantum dot is larger than similar to 30. We find the onset of the spin-droplet regime at nu=5/2. This proposes a finite-geometry alternative to the Moore-Read-type Pfaffian state of the bulk two-dimensional electron gas. Hence, the spin-droplet formation may be related to the observed fragility of the nu=5/2 quantum Hall state in narrow quantum point contacts.
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