Strongly frustrated triangular spin lattice emerging from triplet dimer formation in honeycomb Li2IrO3.
Strongly frustrated triangular spin lattice emerging from triplet dimer formation in honeycomb Li2IrO3.
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DOI：
10.1038/ncomms10273
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发表时间：
2016-01-18
影响因子：
16.6
通讯作者：
van den Brink J
中科院分区：
文献类型：
--
作者：
Nishimoto S;Katukuri VM;Yushankhai V;Stoll H;Rößler UK;Hozoi L;Rousochatzakis I;van den Brink J
具有蜂窝晶格的铱氧化物已被确定为期待已久的基塔耶夫拓扑自旋液体的平台：Ir4+的自旋轨道纠缠态原则上精确地产生所需类型的各向异性交换。然而，其他磁联轴器可以驱动系统远离自旋液相。考虑到这一点，我们在这里解开了Li2IrO3中不同的磁相互作用，Li2IrO3是一种蜂窝状的铱酸盐，具有两组晶体学上不相等的相邻Ir位点。我们的从头算多体计算表明，虽然海森堡和基塔耶夫最近邻耦合都存在，但在一组Ir-Ir键上，前者占主导地位，导致形成自旋三重态二聚体。三重态二聚体构成了一个强烈受挫的三角形晶格，通过精确的簇对角化，我们表明它们在相图的广泛区域内仍然受到保护。蜂窝iridates是实现Kitaev自旋液体的候选材料，具有保护量子信息等特性。本文研究了蜂窝状Li2IrO3的相图，利用量子化学方法推导了相关的有效自旋哈密顿量。
Iridium oxides with a honeycomb lattice have been identified as platforms for the much anticipated Kitaev topological spin liquid: the spin-orbit entangled states of Ir4+ in principle generate precisely the required type of anisotropic exchange. However, other magnetic couplings can drive the system away from the spin-liquid phase. With this in mind, here we disentangle the different magnetic interactions in Li2IrO3, a honeycomb iridate with two crystallographically inequivalent sets of adjacent Ir sites. Our ab initio many-body calculations show that, while both Heisenberg and Kitaev nearest-neighbour couplings are present, on one set of Ir–Ir bonds the former dominates, resulting in the formation of spin-triplet dimers. The triplet dimers frame a strongly frustrated triangular lattice and by exact cluster diagonalization we show that they remain protected in a wide region of the phase diagram. Honeycomb iridates are candidates for the realization of a Kitaev spin liquid, displaying properties such as the protection of quantum information. Here, the authors investigate the phase diagram of honeycomb Li2IrO3, using quantum chemistry methods to derive the relevant effective spin Hamiltonian.