论文标题
应变诱导的轨道分裂对未居库层磁激发的影响
Effect of strain-induced orbital splitting on the magnetic excitations in undoped cuprates
论文作者
论文摘要
鉴于最近的报告，我们研究了磁激发，这表明旋转波能量可能对la $ _2 $ _2 $ cuo $ _4 $的薄膜的平面应变表现出很大的依赖。正如我们发现的那样，依赖性的性质可以自然地基于$ d_ {x^2-y^2} $和$ d_ {3z^2-r^2} $ orbitals的两轨模型。特别是，随着$ d_ {x^2-y^2} $和$ d_ {3z^2-r^2} $轨道之间的轨道拆分能量随着压缩应变而增加，区域内旋转波能量硬化。但是，只有在轨道分裂达到$ \ sim $ 2ev之前，硬化才持续到，除此之外，没有重大变化。区域边界自旋波能量的行为是根据交换式$ d_ {x^2-y^2} $ band之一的杂交程度来解释的，该$ d_ {x^2-y^2} $ band几乎填充了一半，$ d_ {3z^2-r^2} $ band。还讨论了涉及轨道间跳跃的二阶抗磁性超磁性缩减过程的作用。
We investigate the magnetic excitations in view of the recent reports suggesting that the spin-wave energy may exhibit a significant dependence on the in-plane strain of a thin film of La$_2$CuO$_4$. The nature of dependence, as we find, can be explained naturally within a two-orbital model based on the $d_{x^2-y^2}$ and $d_{3z^2-r^2}$ orbitals. In particular, as the orbital-splitting energy between the $d_{x^2-y^2}$ and $d_{3z^2-r^2}$ orbitals increases with compressive strain, the zone-boundary spin-wave energy hardens. However, the hardening persists only until the orbital splitting reaches $\sim$ 2eV, beyond which there is no significant change. The behavior of zone-boundary spin-wave energy is explained in terms of the extent of hybridization between one of the exchange-split $d_{x^2-y^2}$ band which is nearly half filled and the $d_{3z^2-r^2}$ band. The role of second-order antiferromagnetic superexchange process involving the inter-orbital hopping is also discussed.
