论文标题
在磁性亲材材料中增强电荷中立的效率激发\\附近的旋转飞机过渡\\ ybir $ _3 $ si $ _7 $ _7 $
Enhancement of charge-neutral fermionic excitation near spin-flop transition\\ in magnetic Kondo material YbIr$_3$Si$_7$
论文作者
论文摘要
据报道，新型的近托材料ybir $ _3 $ _3 $ _7 $，类似于其他Kondo绝缘子，通过测量在低温下的特定热量和热导率，可以表现出电荷与中性的费米子激发。我们在ybir $ _3 $ _3 $ _7 $上执行了$^{29} $ si-nmr，以从微观的角度研究电荷中性费米子的磁响应。在平行于$ c $轴的低磁场中，顺磁状态中的单个NMR峰分为$ t _ {\ rm n} $以下的三个峰。相比之下，在高磁场中仅观察到单个NMR峰的轻微移动。这种光谱变化是$ c $轴磁场的函数，将其解释为自旋触发器过渡，在该转变下，沿$ c $轴（AF-I相）旋转到具有$ C $ -Axis（AF-II相）的$ C $轴（AF-I相）。在自旋流通磁场的附近$ h _ {\ rm m} $，发现核自旋松弛率$ 1/t_1 $在低温下与温度成正比，表明存在电荷中性效率。此外，$ 1/t_1 $ vs. $ c $轴磁场的峰值表明，Ybir $ _3 $ si $ _7 $中的中性费用与其磁性属性密切相关。我们的发现阐明了绝缘子中电荷中性费米子的起源。
The new Kondo material YbIr$_3$Si$_7$, similar to other Kondo insulators, has been reported to exhibit charge-neutral fermionic excitations through measurements of specific heat and thermal conductivity at low temperatures. We performed $^{29}$Si-NMR on YbIr$_3$Si$_7$ to investigate the magnetic response of charge-neutral fermions from a microscopic perspective. In low magnetic fields parallel to the $c$ axis, a single NMR peak in the paramagnetic state splits into three peaks below $T_{\rm N}$. In contrast, only a slight shift of the single NMR peak was observed in high magnetic fields. This spectral change as a function of the $c$-axis magnetic field is interpreted as spin-flop transition, at which the magnetic moments oriented along the $c$ axis (AF-I phase) are rotated to the $ab$ plane with ferromagnetic component along the $c$-axis (AF-II phase). In the vicinity of the spin-flop magnetic field $H_{\rm M}$, nuclear spin-lattice relaxation rate $1/T_1$ was found to be proportional to temperature at low temperatures, indicating the existence of charge-neutral fermions. Furthermore, a peak of $1/T_1$ vs. the $c$-axis magnetic field suggests that the charge-neutral fermions in YbIr$_3$Si$_7$ are closely related to its magnetic properties. Our findings shed light on the origin of charge-neutral fermions in insulators.
