论文标题
nd $ _ {2-x} $ ce $ _x $ cuo $ _4 $ $ _4 $ _4 $ $ _4 $ $ _4 $ $ _4 $ $ _4 $ $ _4 $ $ _4 $ $ _4 $ $ _4 $的增长后增长后对电荷和旋转激发的退火效果
Post-growth annealing effects on charge and spin excitations in Nd$_{2-x}$Ce$_x$CuO$_4$
论文作者
论文摘要
我们报告了cu k-和l $ _3 $ - 边缘谐振X射线散射研究，对散装nd $ _ {2-x} $ _ {2-x} $ _x $ _x $ cuo $ _4 $的旋转激发研究，重点关注生殖后退火效果。对于父级化合物nd $ _2 $ cuo $ _4 $（$ x = 0 $），在随着的状态下观察到明显的费用转移差距，而电荷激发光谱表明电子在退火状态下掺杂。这与观察到的观察结果是，Re $ _2 $ cuo $ _4 $（re =稀土）的退火薄膜和多晶样品可以成为金属，并且以足够高的电子浓度而无需CE CE掺杂。对于$ x = 0.16 $，众所周知，氧气减少的浓度会破坏远程抗铁磁秩序并诱导超导性，我们发现非渗透导致的高渗透旋转激发因素而成长，而超导超导的晶体几乎相同。这一发现与先前通过中子散射观察到的低能自旋激发的显着变化形成鲜明对比。
We report a Cu K- and L$_3$-edge resonant inelastic x-ray scattering study of charge and spin excitations of bulk Nd$_{2-x}$Ce$_x$CuO$_4$, with focus on post-growth annealing effects. For the parent compound Nd$_2$CuO$_4$ ($x = 0$), a clear charge-transfer gap is observed in the as-grown state, whereas the charge excitation spectra indicate that electrons are doped in the annealed state. This is consistent with the observation that annealed thin-film and polycrystalline samples of RE$_2$CuO$_4$ (RE = rare earth) can become metallic and superconducting at sufficiently high electron concentrations without Ce doping. For $x = 0.16$, a Ce concentration for which it is known that oxygen reduction destroys long-range antiferromagnetic order and induces superconductivity, we find that the high-energy spin excitations of non-superconducting as-grown and superconducting annealed crystals are nearly identical. This finding is in stark contrast to the significant changes in the low-energy spin excitations previously observed via neutron scattering.
