How to probe a fractionally charged quasihole?

• Published in: Physica. E, Low-dimensional systems & nanostructures Low-dimensional systems & nanostructures, 2004-04, Vol.22 (1), p.131-134, Article 131
• Main Authors: Schüller, C., Broocks, K.-B., Schröter, P., Heyn, Ch, Heitmann, D., Bichler, M., Wegscheider, W., Chakraborty, T., Apalkov, V.M.
• Format: Article
• Language: English
• Subjects: Fractionally charged particles; Photoluminescence; Quantum Hall effect
• ISSN: 1386-9477; 1873-1759
• DOI: 10.1016/j.physe.2003.11.233

We report an anomalous dispersion of charged excitons in photoluminescence experiments on a two-dimensional electron gas subjected to a quantizing magnetic field around ν= 1 3 . We have found that the anomaly exists only at a very low temperature (0.1 K) and an intermediate electron density (0.9×10 11 cm −2) . It is explained to occur due to the perturbation of the incompressible liquid at ν= 1 3 . The perturbation is induced by the close proximity of a localized charged exciton which creates a fractionally charged quasihole in the liquid. The intriguing experimentally observed puzzle that the anomaly can be destroyed by applying a small thermal energy of ∼0.2 meV is thereby resolved, as this energy is enough to close the quasihole energy gap. This work presents a probe of the quasihole gap in a quantum Hall system.