Transference of Fermi Contour Anisotropy to Composite Fermions

Insun Jo, K. A.Villegas Rosales, M. A. Mueed, L. N. Pfeiffer, K. W. West, K. W. Baldwin, R. Winkler, Medini Padmanabhan, M. Shayegan

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


There has been a surge of recent interest in the role of anisotropy in interaction-induced phenomena in two-dimensional (2D) charged carrier systems. A fundamental question is how an anisotropy in the energy-band structure of the carriers at zero magnetic field affects the properties of the interacting particles at high fields, in particular of the composite fermions (CFs) and the fractional quantum Hall states (FQHSs). We demonstrate here tunable anisotropy for holes and hole-flux CFs confined to GaAs quantum wells, via applying in situ in-plane strain and measuring their Fermi wave vector anisotropy through commensurability oscillations. For strains on the order of 10-4 we observe significant deformations of the shapes of the Fermi contours for both holes and CFs. The measured Fermi contour anisotropy for CFs at high magnetic field (αCF) is less than the anisotropy of their low-field hole (fermion) counterparts (αF), and closely follows the relation αCF=αF. The energy gap measured for the ν=2/3 FQHS, on the other hand, is nearly unaffected by the Fermi contour anisotropy up to αF∼3.3, the highest anisotropy achieved in our experiments.

Original languageEnglish (US)
Article number016402
JournalPhysical review letters
Issue number1
StatePublished - Jul 7 2017

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


Dive into the research topics of 'Transference of Fermi Contour Anisotropy to Composite Fermions'. Together they form a unique fingerprint.

Cite this