论文标题
在B20 coge中，可能的四极级驱动的相应相应的相变
Possible quadrupole-order-driven commensurate-incommensurate phase transition in B20 CoGe
论文作者
论文摘要
通过测量特定的热，电阻率和$^{59} $ co核磁共振（NMR）来研究B20型钴Germanide coge。我们观察到$ t_q = 13.7 $ k的相变，这是由核自旋旋转（$ t_2^{ - 1} $）的特定热量和急剧变化的非常狭窄的峰和旋转粘合（$ t_1^{ - 1} $）放松率的峰值所证明的。熵释放非常小，骑士移位几乎独立于温度向低温到低温，这一事实表明$ t_q $ transition的过渡是非磁性的。此外，我们检测到了一个交叉标度$ T_0 \ sim30 $ K，在该$ k下增加了电阻率和NMR线宽，而$ t_1^{ - 1} $在太空中逐渐分布，也就是说，即静态而动态的空间不合理性。 While the order parameter for the $T_Q$ transition remains an open question, a group-theoretical analysis suggests that the finite electric quadrupole density arising from the low local site symmetry at cobalt sites could drive the crystal symmetry lowering from the P2$_1$3 symmetry that is commensurate to the R3 symmetry with an incommensurate wavevector, which fairly well accounts for the $T_Q$ transition.四极级驱动的相称 - 相应的相变可能是由非中性对称B20家族固有的结构性手性引起的另一个显着现象。
The B20-type cobalt germanide CoGe was investigated by measuring the specific heat, resistivity, and $^{59}$Co nuclear magnetic resonance (NMR). We observed a phase transition at $T_Q=13.7$ K, evidenced by a very narrow peak of the specific heat and sharp changes of the nuclear spin-spin ($T_2^{-1}$) and spin-lattice ($T_1^{-1}$) relaxation rates. The fact that the entropy release is extremely small and the Knight shift is almost independent of temperature down to low temperatures as anticipated in a paramagnetic metal indicates that the $T_Q$ transition is of non-magnetic origin. In addition, we detected a crossover scale $T_0\sim30$ K below which the resistivity and the NMR linewidth increase, and $T_1^{-1}$ is progressively distributed in space, that is, a static and dynamical spatial inhomogeneity develops. While the order parameter for the $T_Q$ transition remains an open question, a group-theoretical analysis suggests that the finite electric quadrupole density arising from the low local site symmetry at cobalt sites could drive the crystal symmetry lowering from the P2$_1$3 symmetry that is commensurate to the R3 symmetry with an incommensurate wavevector, which fairly well accounts for the $T_Q$ transition. The quadrupole-order-driven commensurate-incommensurate phase transition may be another remarkable phenomenon arising from the structural chirality inherent in the noncentrosymmetric B20 family.
