在温度为0.05 ~ 300 K，磁场高达9 T的条件下，测量了载流子掺杂磁性半导体Fe $_{1-x}$ Co $_x$ S $_2$的$0\le x \le 0.16$的霍尔效应和电阻率。我们的霍尔数据表明电子电荷载流子的密度仅为我们晶体的Co密度的10%至30%。尽管以前的识别磁性格里菲斯相形成的磁性和热力学性质的这个系统的相同范围的$x$，我们测量温度无关的电阻率低于0.5 K表示费米液体运输。我们也没有观察到量子校正的电导率，尽管费米波矢量和平均自由程，$1.5 \le k_F\ell \le 15$的产品的小值，在范围内的$x$调查。这意味着一个大的非弹性散射率，这样的必要条件，观察量子贡献的载流子传输，量子相干时间远长于弹性散射时间，是不符合我们的样品。高于0.5 K，我们观察到的温度和磁场依赖的电阻率，非常类似于近藤异常的$x$小于所需的形成一个长距离的磁性状态，$x_c$。对于$x>x_c$，电阻率和磁阻类似于自旋玻璃，在5 T场中电阻率降低多达35%。我们还观察到增强的残余电阻率比的样品与$x\sim x_c$表示温度相关的散射机制超出简单的载流子-声子散射的几乎2倍。我们推测，这种增强是由于电荷载流子散射的磁波动，这有助于在很宽的温度范围内的电阻率。
英文摘要：
The Hall effect and resistivity of the carrier doped magnetic semiconductor Fe$_{1-x}$Co$_x$S$_2$ were measured for $0\le x \le 0.16$, temperatures between 0.05 and 300 K, and fields of up to 9 T. Our Hall data indicate electron charge carriers with a density of only 10 to 30% of the Co density of our crystals. Despite the previous identification of magnetic Griffiths phase formation in the magnetic and thermodynamic properties of this system for the same range of $x$, we measure a temperature independent resistivity below 0.5 K indicating Fermi liquid-like transport. We also observe no indication of quantum corrections to the conductivity despite the small values of the product of the Fermi wave vector and the mean-free-path, $1.5 \le k_F\ell \le 15$, over the range of $x$ investigated. This implies a large inelastic scattering rate such that the necessary condition for the observation of quantum contributions to the carrier transport, quantum coherence over times much longer than the elastic scattering time, is not met in our samples. Above 0.5 K we observe a temperature and magnetic field dependent resistivity that closely resembles a Kondo anomaly for $x$ less than that required to form a long range magnetic state, $x_c$. For $x>x_c$, the resistivity and magnetoresistance resemble that of a spin glass with a reduction of the resistivity by as much as 35% in 5 T fields. We also observe an enhancement of the residual resistivity ratio by almost a factor of 2 for samples with $x\sim x_c$ indicating temperature dependent scattering mechanisms beyond simple carrier-phonon scattering. We speculate that this enhancement is due to charge carrier scattering from magnetic fluctuations which contribute to the resistivity over a wide temperature range.
Conductance and Kondo effect of a controlled single atom contact
使低温扫描隧道显微镜的尖端与吸附在Cu（100）表面上的单个近藤杂质（钴原子）接触。发生从隧穿区到电导为$G\approx\text{G}_0$的点接触的平滑过渡。接触状态下的光谱，{ \it i. e.}，在$μ\text{A}$范围内的电流下实现。观察到改变的线形，表明接触时近藤温度$T_{\text{K}}$的显著变化。模型计算表明，尖端的接近移动了钴$d$带，从而影响了$T_{\text{K}}$ .
Dependence of transport coefficients of Yb(Rh$_{1-x}$Co$_x$)$_2$Si$_2$ intermetallics on temperature and cobalt concentration
采用考虑了传导电子在镱离子上的交换散射和电场对$f$ 4态分裂的非对称Anderson模型，解释了Yb（Rh $_{1-x}$ Co $_x$）$_2$ Si $_2$系列合金的输运系数与温度和钴浓度的关系.用钴取代铑被描述为化学压力的增加，其减少了交换耦合和CEF分裂。对模型的标度分析和数值NCA解表明，在给定温度下4 $f$态的有效简并度依赖于近藤尺度和CEF分裂的相对大小.因此，我们发现，热电势，$S(T)$，对温度和钴浓度的依赖性，可以理解为量子涨落的相互作用，由近藤效应驱动，和热波动，这有利于均匀占领的CEF状态。理论模型捕捉了实验数据的所有定性特征，并解释了$S(T)$的形状随钴浓度的增加而演变。
