Yadav Ravi, Eldeeb Mohamed S, Ray Rajyavardhan, Aswartham Saicharan, Sturza Mihai I, Nishimoto Satoshi, van den Brink Jeroen, Hozoi Liviu
Leibniz Institute for Solid State and Materials Research , IFW Dresden , Helmholtzstr. 20 , 01069 Dresden , Germany . Email:
Dresden Center for Computational Materials Science (DCMS) , TU Dresden , 01062 Dresden , Germany.
Chem Sci. 2018 Dec 3;10(6):1866-1872. doi: 10.1039/c8sc03018a. eCollection 2019 Feb 14.
Novel functionalities may be achieved in oxide electronics by appropriate stacking of planar oxide layers of different metallic species, MO and M'O . The simplest mechanism allowing the tailoring of the electronic states and physical properties of such heterostructures is of electrostatic nature-charge imbalance between the M and M' cations. Here we clarify the effect of interlayer electrostatics on the anisotropic Kitaev exchange in HLiIrO, a recently proposed realization of the Kitaev spin liquid. By quantum chemical calculations, we show that the precise position of H cations between magnetically active [LiIrO] honeycomb-like layers has a strong impact on the magnitude of Kitaev interactions. In particular, it is found that stacking with straight interlayer O-H-O links is detrimental to in-plane Kitaev exchange since coordination by a single H-ion of the O ligand implies an axial Coulomb potential at the O site and unfavorable polarization of the O 2p orbitals mediating the Ir-Ir interactions. Our results therefore provide valuable guidelines for the rational design of Kitaev quantum magnets, indicating unprecedented Kitaev interactions of ≈40 meV if the linear interlayer linkage is removed.
通过对不同金属种类的平面氧化物层MO和M'O进行适当堆叠，可以在氧化物电子学中实现新的功能。允许调整此类异质结构的电子态和物理性质的最简单机制是静电性质——M和M'阳离子之间的电荷不平衡。在此，我们阐明了层间静电对HLiIrO中各向异性Kitaev交换的影响，HLiIrO是最近提出的Kitaev自旋液体的一种实现方式。通过量子化学计算，我们表明H阳离子在磁性活性[LiIrO]蜂窝状层之间的精确位置对Kitaev相互作用的大小有强烈影响。特别是，发现具有直的层间O-H-O键的堆叠不利于面内Kitaev交换，因为O配体由单个H离子配位意味着O位点处的轴向库仑势以及介导Ir-Ir相互作用的O 2p轨道的不利极化。因此，我们的结果为Kitaev量子磁体的合理设计提供了有价值的指导方针，表明如果去除线性层间连接，将出现前所未有的约40 meV的Kitaev相互作用。
