Even-denominator fractional quantum Hall effect at a Landau level crossing

Journal Article · Tue Apr 01 00:00:00 EDT 2014 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PhysRevB.89.165313· OSTI ID:1352837

Liu, Yang; Hasdemir, S.; Kamburov, D.; Graninger, A. L.; Shayegan, M.; Pfeiffer, L. N.; West, K. W.; Baldwin, K. W.; Winkler, R.

The fractional quantum Hall effect (FQHE), observed in two-dimensional (2D) charged particles at high magnetic fields, is one of the most fascinating, macroscopic manifestations of a many-body state stabilized by the strong Coulomb interaction. It occurs when the filling factor (v) of the quantized Landau levels (LLs) is a fraction, which, with very few exceptions, has an odd denominator. In 2D systems with additional degrees of freedom it is possible to cause a crossing of the LLs at the Fermi level. At and near these crossings, the FQHE states are often weakened or destroyed. Here we report the observation of an unusual crossing of the two lowest-energy LLs in high-mobility GaAs 2D hole systems, which brings to life a new even-denominator FQHE v = 1/2.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: National Science Foundation (NSF); USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1352837
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 89, Issue 16; ISSN 1098-0121
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English