title: Quantum oscillations in the underdoped cuprate YBa2Cu4O8.
abstract: We report the observation of quantum oscillations in the underdoped cuprate superconductor YBa2Cu4O8 using a tunnel-diode oscillator technique in pulsed magnetic fields up to 85 T. There is a clear signal, periodic in inverse field, with frequency 660+/-15 T and possible evidence for the presence of two components of slightly different frequency. The quasiparticle mass is m(*)=3.0+/-0.3m(e). In conjunction with the results of Doiron-Leyraud et al. for YBa2Cu3O6.5, the present measurements suggest that Fermi surface pockets are a general feature of underdoped copper oxide planes and provide information about the doping dependence of the Fermi surface.
authors: H. H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, United Kingdom.
authors: E A
authors: EA
authors: Yelland
authors: J
authors: J
authors: Singleton
authors: C H
authors: CH
authors: Mielke
authors: N
authors: N
authors: Harrison
authors: F F
authors: FF
authors: Balakirev
authors: B
authors: B
authors: Dabrowski
authors: J R
authors: JR
authors: Cooper