Abstract
We present a detailed study of quantum oscillations in the antiferromagnetically ordered pnictide compound SrFeAs as the angle between the applied magnetic field and crystalline axes is varied. Our measurements were performed on high-quality single crystals in a superconducting magnet, and in pulsed magnetic fields up to 60 T, allowing us to observe orbits from several small Fermi-surface pockets. We extract the cyclotron effective mass and frequency for these orbits and track their values as the field is rotated away from the axis. While a constant ratio of is expected for a parabolic band, we observe deviations from this behavior. We conclude that this observation points to orbits derived from a band with Dirac dispersion near the Fermi level.
- Received 8 July 2011
DOI:https://doi.org/10.1103/PhysRevB.84.180506
©2011 American Physical Society