Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, D-85748 Garching, Germany.
Phys Rev Lett. 2009 Oct 9;103(15):157002. doi: 10.1103/PhysRevLett.103.157002. Epub 2009 Oct 5.
We report on the direct probing of the Fermi surface in the bulk of the electron-doped superconductor Nd(2-x)Ce(x)CuO(4) at different doping levels by means of magnetoresistance quantum oscillations. Our data reveal a sharp qualitative change in the Fermi surface topology, due to translational symmetry breaking in the electronic system which occurs at a critical doping level significantly exceeding the optimal doping. This result implies that the (pi/a, pi/a) ordering, known to exist at low doping levels, survives up to the overdoped superconducting regime.
我们通过磁阻量子震荡的方法直接探测了在不同掺杂水平的电子掺杂超导 Nd(2-x)Ce(x)CuO(4) 体相中费米面的情况。我们的数据揭示了费米面拓扑结构的一个明显的定性变化，这是由于电子系统中的平移对称性被破坏，这种破坏发生在一个远远超过最佳掺杂的临界掺杂水平。这个结果意味着在低掺杂水平下存在的（pi/a，pi/a）有序，一直持续到过掺杂超导区域。
