论文标题
Spin-1/2三角形抗fiferromagnet na $ _ {2} $ ba $ _ {1-x} $ sr $ _ {x} $ co（po $ _ {4} $ _ {2} $ _ {2} $）
Doping-induced structural transformation in the spin-1/2 triangular-lattice antiferromagnet Na$_{2}$Ba$_{1-x}$Sr$_{x}$Co(PO$_{4}$)$_{2}$
论文作者
论文摘要
Sr掺杂对Na $ _ {2} $ BACO（PO $ _ {4} $）$ _ {2} $的结构特性的影响，一种spin-1/2三角形 - 静态抗fiferromagnet作为量子旋转液体候选者，由互补的X射线和中子X射线和中子粉末粉化量进行研究。发现在Na $ _ {2} $ ba $ _ {1-x} $ sr $ _ {x} $ co（po $ _ {4} $）$ _ {2} $（nbscpo），trigonal阶段（太空集团$ \ mathit $ \ mathit {p} $ \ bar}当Sr的掺杂水平低于30％时，Co $^{2+} $离子的三角形晶格在结构上是稳定的（$ \ Mathit {x} $ $ \ le $ 0.3），而纯单晶阶段（纯净的单晶相位（太空集团$ \ \ \ \ m athit {p} COO $ _ {6} $ contahedra和Ba $^{2+} $/sr $^{2+} $ ions的位移，当SR掺杂级别高于60％（$ \ Mathit {x} $ $ \ ge $ 0.6）时，将建立$ ions。这种兴奋剂引起的NBSCPO中的结构转化得到了第一原理的计算和拉曼光谱的支持。 na $ _ {2} $ srco（po $ _ {4} $）$ _ {2} $，一种新颖的spin-1/2三角形 - 静态反铁磁体，带有glaserite-type结构，尽管单渠道上扭曲了，但没有显示出2 k和类似的负频率的磁性磁序Na $ _ {2} $ baco（po $ _ {4} $）$ _ {2} $带有完美的三角形晶格，这表明磁性交换相互作用与BA/SR替换的稳健性。
The effects of Sr doping on the structural properties of Na$_{2}$BaCo(PO$_{4}$)$_{2}$, a spin-1/2 triangular-lattice antiferromagnet as a quantum spin liquid candidate, are investigated by complementary x-ray and neutron powder diffraction measurements. It is found that in Na$_{2}$Ba$_{1-x}$Sr$_{x}$Co(PO$_{4}$)$_{2}$ (NBSCPO), the trigonal phase (space group $\mathit{P}$$\bar{3}$$\mathit{m}$1) with a perfect triangular lattice of Co$^{2+}$ ions is structurally stable when the doping level of Sr is below 30% ($\mathit{x}$ $\le$ 0.3), while a pure monoclinic phase (space group $\mathit{P}$2$_{1}$/$\mathit{a}$) with slight rotations of CoO$_{6}$ octahedra and displacements of Ba$^{2+}$/Sr$^{2+}$ ions will be established when the Sr doping level is above 60% ($\mathit{x}$ $\ge$ 0.6). Such a doping-induced structural transformation in NBSCPO is supported by first-principles calculations and Raman spectroscopy. Na$_{2}$SrCo(PO$_{4}$)$_{2}$, a novel spin-1/2 triangular-lattice antiferromagnet with glaserite-type structure, although monoclinically distorted, exhibits no long-range magnetic order down to 2 K and a similar negative Curie-Weiss temperature as Na$_{2}$BaCo(PO$_{4}$)$_{2}$ with a perfect triangular lattice, suggesting the robustness of magnetic exchange interaction against the Ba/Sr substitutions.
