Thursday, September 6, 2007

Antiphase Stripe Order as the Origin of Electron Pockets Observed in 1/8-Hole-Doped Cuprates

Recent magneto-transport experiments in very large magnetic fields reveal Shubnikov-de Haas oscillations in the "normal" state of YBCO (see for example Shubnikov-de Haas oscillations in YBa_2Cu_4O_8). The magnetic fields, on the order of 60T suppress the superconductivity allowing a study of the normal state down to low temperatures. The simplest interpretation of the observed "quantum" oscillations, as they are sometimes called, is that they correspond to the formation of four small Fermi surfaces called "pockets".

In this paper, the authors consider the breakup of a large Fermi surface due to the presence of "anti-phase stripe" ordering. After D-wave superconductivity and antiferromagnetism, this ordering is the next most well established in the cuprates, known to suppress superconductivity near x=1/8 doping in LSCO and LBCO. They show that a robust region of their parameter space correspond to electron-like pockets, which are not easily explained by pure antiferromagnetic order. Thus they propose that this anti-phase stripe ordering is induced in YBCO at finite magnetic field and that its inflouence may be generic to all cuprates.