论文标题
4F1 Delafossite磁铁中的能量尺度：晶体场分裂大于KCEO2中自旋轨道耦合的强度
Energy scales in 4f1 delafossite magnets: crystal-field splittings larger than the strength of spin-orbit coupling in KCeO2
论文作者
论文摘要
对具有有效S = 1/2矩的基于ytterbium的Delafoss进行了大量研究，作为量子自旋式接地状态的候选者。虽然还报道了相关葡萄剂化合物的合成，但有关其晶体，电子和磁性结构的许多重要细节尚不清楚。在这里，我们分析了S = 1/2系统KCEO2，结合了互补的理论方法。优化了晶格的几何形状，并使用密度功能理论进行了研究，以扩展到GGA+U计算水平，以重现正确的绝缘行为。然后，在基于Ab intio波功能的计算的帮助下，对CE 4F1状态进行了更详细的详细分析。预计将预测高达320 MeV的异常有效的晶体场分裂，这将KCEO2置于强场耦合方案中。我们的结果揭示了配体元素静电和由扩展的结晶环境产生的三角球场之间的微妙相互作用，这与最近在4F三角形岩石和pyrochlore化合物中调谐地面波功能的性质的研究有关。它还使KCEO2成为有趣的模型系统，与大型晶体场分裂对自旋轨道耦合量子磁体中现场交换各向异性的影响有关。
Ytterbium-based delafossites with effective S=1/2 moments are investigated intensively as candidates for quantum spin-liquid ground states. While the synthesis of related cerium compounds has also been reported,many important details concerning their crystal, electronic, and magnetic structures are unclear. Here we analyze the S=1/2 system KCeO2, combining complementary theoretical methods. The lattice geometry was optimized and the band structure investigated using density functional theory extended to the level of a GGA+U calculation in order to reproduce the correct insulating behavior. The Ce 4f1 states were then analyzed in more detail with the help of ab initio wave-function-based computations. Unusually large effective crystal-field splittings of up to 320 meV are predicted, which puts KCeO2 in the strong field coupling regime. Our results reveal a subtle interplay between ligand-cage electrostatics and the trigonal field generated by the extended crystalline surroundings, relevant in the context of recent studies on tuning the nature of the ground-state wave function in 4f triangular-lattice and pyrochlore compounds. It also makes KCeO2 an interesting model system in relation to the effect of large crystal-field splittings on the anisotropy of intersite exchange in spin-orbit coupled quantum magnets.
