建立控制交换相互作用的物理机制是探索诸如实际材料中的量子自旋液体（QSL）等奇异相的基础。在这项工作中，我们解决交换相互作用的Sr 2CuTe $_{1-x}$ W $_{x}$ O，一系列的双钙钛矿，实现自旋1/2的正方形晶格，并建议窝藏QSL基态所产生的随机分布的非磁性离子。我们的{ \it ab initio}多参考组态相互作用计算表明，用W原子取代Te原子改变了由最近邻到次最近邻的主导耦合，解释了非磁性离子的未占态在超超交换机制中的关键作用。结合自旋波理论模拟，我们计算的交换耦合提供了一个很好的描述的非弹性中子散射光谱的终端化合物，以及解释的磁激发在Sr 2 CuTe $_{0.5}$ W $_{0.5}$ O作为新兴的键无序交换耦合。我们的研究结果提供了至关重要的理解交换相互作用中的非磁性阳离子的作用铺平了道路，以进一步探索QSL相键无序材料。
英文摘要：
Establishing the physical mechanism governing exchange interactions is fundamental for exploring exotic phases such as the quantum spin liquids (QSLs) in real materials. In this work, we address exchange interactions in Sr2CuTe$_{1-x}$W$_{x}$O, a series of double perovskites that realize the spin-1/2 square lattice and were suggested to harbor a QSL ground state arising from random distribution of non-magnetic ions. Our {\it ab initio} multi-reference configuration interaction calculations show that replacing Te atoms with W atoms changes the dominant couplings from nearest to next-nearest neighbor explained by the crucial role of unoccupied states of non-magnetic ions in the super-superexchange mechanism. Combined with spin-wave theory simulations, our calculated exchange couplings provide an excellent description of the inelastic neutron scattering spectra of the end compounds, as well as explain the magnetic excitations in Sr2CuTe$_{0.5}$W$_{0.5}$O as emerging from the bond-disordered exchange couplings. Our results provide crucial understanding of the role of non-magnetic cations in exchange interactions paving the way to further exploration of QSL phases in bond-disordered materials.
Effect of pressure on the order-disorder phase transitions of $B$-cations in $AB'_{1/2}B''_{1/2}$O$_3$ perovskites
类钙钛矿氧化物$AB'_{1/2}B''_{1/2}$ O $_3$可经历不同的$B$ -阳离子有序度，其可通过合适的合成条件或合成后处理而变化。在这项工作中，较早提出的统计模型的有序-无序相变的$B$ -阳离子扩展到占压力的影响。根据组成，压力被发现要么增加或减少的有序-无序相变温度。在实验室可达到的压力下，相变温度随压力的变化在许多情况下可达几百K，这可能会显著改变原子的有序度。这项工作旨在帮助确定压力如何影响原子有序度，并刺激研究压力对钙钛矿中原子有序-无序相变的影响。
Influence of the $A$ cation on the low-temperature antiferromagnetism of ordered antiferroelectric $A_2$CoTeO$_6$ perovskites
我们研究了反铁电$A_2$ CoTeO $_6$钙钛矿（其中$A$ = Cd，Ca，Sr，Pb，Ba）的结构和磁性。所有化合物在低温下都是反铁磁性的，反铁磁性转变温度随着$A$阳离子的离子尺寸的减小而略微降低。在$A^{2+}_2$ Co $M^{6+}$ O $_6$材料中没有观察到反铁磁相互作用的这种减少，这表明Te $^{6+}$阳离子影响系统的电子结构，进而影响系统的磁结构。
Magnetic excitations in double perovskite iridates La$_{2}$$\mathit{M}$IrO$_{6}$ ($\mathit{M}$ = Co, Ni, and Zn) mediated by 3$\mathit{d}$-5$\mathit{d}$ hybridization
A comparative study on magnetic order and field induced magnetic transition on two series of double perovskite iridates RE2BIrO6 (RE=Pr,Nd,Sm,Eu,Gd B=Zn,Mg)
