标题： 海森堡-基塔耶夫模型的有限温度相图 显示英文标题

标题： Finite-temperature phase diagram of the Heisenberg-Kitaev model

摘要： 我们讨论了六边形晶格上的海森堡-基塔夫模型的有限温度相图，该模型被认为可以描述莫特绝缘体Ir基化合物Na2IrO3中有效自旋-1/2矩的自旋轨道交换作用。在零温度下，该模型表现出超出各向同性海森堡极限的磁有序态，以及围绕高度各向异性基塔夫极限的扩展无能隙自旋液体相。使用伪费米子功能重整化群（RG）方法，我们从磁化率的RG流中提取了居里-韦斯尺度和临界有序尺度（对于磁有序态）。居里-韦斯尺度改变符号——表明主要交换作用从反铁磁转变为铁磁——在磁有序区域深处。对于后者，我们发现没有显著的挫折，即相对于居里-韦斯尺度，有序尺度有显著抑制。我们根据最近对Na2IrO3的实验磁化率测量结果讨论了我们的结果。 显示英文摘要

摘要： We discuss the finite-temperature phase diagram of the Heisenberg-Kitaev model on the hexagonal lattice, which has been suggested to describe the spin-orbital exchange of the effective spin-1/2 momenta in the Mott insulating Iridate Na2IrO3. At zero-temperature this model exhibits magnetically ordered states well beyond the isotropic Heisenberg limit as well as an extended gapless spin liquid phase around the highly anisotropic Kitaev limit. Using a pseudofermion functional renormalization group (RG) approach, we extract both the Curie-Weiss scale and the critical ordering scale (for the magnetically ordered states) from the RG flow of the magnetic susceptibility. The Curie-Weiss scale switches sign -- indicating a transition of the dominant exchange from antiferromagnetic to ferromagnetic -- deep in the magnetically ordered regime. For the latter we find no significant frustration, i.e. a substantial suppression of the ordering scale with regard to the Curie-Weiss scale. We discuss our results in light of recent experimental susceptibility measurements for Na2IrO3.