论文标题
三角晶格抗fiferromagnet na2baco（PO4）2的导热率：不存在巡回效率激发
Thermal conductivity of triangular-lattice antiferromagnet Na2BaCo(PO4)2: Absence of itinerant fermionic excitations
论文作者
论文摘要
我们介绍了三角形 - 粘液抗fifermagnet na $ _2 $ baco（po $ _4 $）$ _ 2 $的单晶晶体抗fiferromagnet na $ _ 2 $的超温度的特异性热和热导率测量，最近被认为是托管流动的触发效率，例如notalant fermionic兴奋，例如量子的液体，例如0. K.在特定的热量测量中，我们确认磁场$μ_0h \ leq $ 1 t时由于抗磁磁有序的峰值，大致与先前的工作一致[N. N. li $ et $ $ al。$，nat。社区。 11，4216（2020）]。但是，在热导率测量中，我们观察到零和有限磁场的残留线性项可忽略不计，与先前的报告形成鲜明对比[N. li $ et $ $ al。$，nat。社区。 11，4216（2020）]。在0.35 K时，热导率随场饱和而饱和，类似于另一个三角晶格化合物ybmggao $ _4 $，这进一步表明热量仅由旋转和边界散射的声子进行。我们的结果清楚地表明，在这种令人沮丧的抗fiferromagnet na $ _2 $ baco（po $ _4 $）$ _ 2 $中，在$ t _ {\ rm n} $的无序状态下缺乏巡回的效率激发，因此这种状态不像先前报道的那样兴奋。
We present the ultralow-temperature specific heat and thermal conductivity measurements on single crystals of triangular-lattice antiferromagnet Na$_2$BaCo(PO$_4$)$_2$, which was recently argued to host itinerant fermionic excitations, like a quantum spin liquid, above its antiferromagnetic phase transition temperature $T_{\rm N}$ = 0.148 K. In specific heat measurements, we confirm the peaks due to antiferromagnetic ordering when magnetic field $μ_0 H \leq$ 1 T, roughly consistent with previous work [N. Li $et$ $al.$, Nat. Commun. 11, 4216 (2020)]. However, in thermal conductivity measurements, we observe negligible residual linear term in zero and finite magnetic fields, in sharp contrast to previous report [N. Li $et$ $al.$, Nat. Commun. 11, 4216 (2020)]. At 0.35 K, the thermal conductivity increases with field up to 3 T then saturates, similar to that of another triangular-lattice compound YbMgGaO$_4$, which further shows that the heat is conducted only by phonons with scattering from spins and boundary. Our results clearly demonstrate the absence of itinerant fermionic excitations in the disordered state above $T_{\rm N}$ in this frustrated antiferromagnet Na$_2$BaCo(PO$_4$)$_2$, thus such a state is not as exotic as previously reported.
