论文标题
对两个方形kagome抗fiferromagnets的低温特异性研究
Low-temperature specific-heat studies on two square-kagome antiferromagnets
论文作者
论文摘要
我们研究了具有二维方形 - kagome结构的两个反铁磁体的低温比热，即kcu $ _6 $ _6 $ albio $ _4 $（SO $ _4 $）$ _ 5 $ cl（kcu6）和na $ _6 $ cu $ _7 $ bio $ _4 $（po $ _4 $）$ _ 4 $ [cl，（oh）] $ _ 3 $（nacu7）具有结构上的差异，即NaCu7中有Interlayer Cu $^{2+} $ ions。两种材料都没有磁性排序降至50 mk。在零字段，当温度接近零K时，kCU6的$ c/t $具有有限的值。在磁场下，出现了$ t^2 $依赖性，并且其系数被该场逐渐抑制。对于NACU7，特定的热量在零场和磁场下表现出$ t^2 $依赖性。在高场上KCU6和NaCU7的二次系数的比例与平方Weiss温度的比例成反比，这表明这两种化合物在场下具有相同的基态。我们的结果表明，NACU7中的层间Cu $^{2+} $离子在确定其基态中起忽略不计。我们讨论了这些化合物中可能的量子旋转状态，以及基于我们的结果追求的进一步方向。
We studied the low-temperature specific heats of two antiferromagnets with the two-dimensional square-kagome structure, i.e., KCu$_6$AlBiO$_4$(SO$_4$)$_5$Cl (KCu6) and Na$_6$Cu$_7$BiO$_4$(PO$_4$)$_4$[Cl,(OH)]$_3$ (NaCu7) with the structural differences that there are interlayer Cu$^{2+}$ ions in NaCu7. Both materials show no magnetic ordering down to 50 mK. At zero field, the $C/T$ of KCu6 has a finite value when the temperature is close to zero K. Under the magnetic field, a seemingly $T^2$ dependence appears and its coefficient is progressively suppressed by the field. For NaCu7, the specific heat exhibits the $T^2$ dependence at zero field and under fields. The ratio of the quadratic coefficients of KCu6 and NaCu7 at high fields is inversely proportional to ratio of the squared Weiss temperatures, which indicates these two compounds host the same ground state under fields. Our results suggest that the interlayer Cu$^{2+}$ ions in NaCu7 play a negligible role in determination of its ground state. We discuss the possible quantum-spin-liquid states in these compounds and further directions to pursue based our results.
