Screened moments and extrinsic in-gap states in samarium hexaboride.
Screened moments and extrinsic in-gap states in samarium hexaboride.
复制标题
DOI：
10.1038/s41467-018-04007-z
复制
发表时间：
2018-04-18
影响因子：
16.6
通讯作者：
Broholm CL
中科院分区：
文献类型：
--
作者：
Fuhrman WT;Chamorro JR;Alekseev PA;Mignot JM;Keller T;Rodriguez-Rivera JA;Qiu Y;Nikolić P;McQueen TM;Broholm CL
六硼化钐 (SmB6) 是一种近藤绝缘体，由于局域电子和传导电子之间的杂化而具有很窄的能隙。尽管是绝缘体，许多样品仍表现出类似金属的特性。稀土提纯极其困难，名义上纯的样品可能含有 2% 或更多的杂质。为了确定稀土掺杂对 SmB6 的影响，我们合成并探测了一系列掺钆样品。我们发现比热和杂质矩筛选之间存在系统扩展的关系。与这一发现一致，我们对高纯度双同位素 154Sm11B6 样品进行的中子散射实验表明，在公认的 13meV 自旋激子以下没有内在激发。将杂质引入近藤绝缘体的结果尚不完全清楚，但从我们的测量中可以清楚地看出，稀土杂质与 SmB6 中的类金属特性之间存在系统关系。六硼化钐的非常规行为很难解释，部分原因是样品之间存在差异。在这里，作者使用钆来举例说明难以避免的杂质引入了低能量密度的状态，这可能解释了早期的观察结果。
Samarium hexaboride (SmB6) is a Kondo insulator, with a narrow gap due to hybridization between localized and conduction electrons. Despite being an insulator, many samples show metal-like properties. Rare-earth purification is exceedingly difficult, and nominally pure samples may contain 2% or more of impurities. Here to determine the effects of rare-earth doping on SmB6, we synthesized and probed a series of gadolinium-doped samples. We found a relationship between specific heat and impurity moment screening which scales systematically. Consistent with this finding, our neutron scattering experiments of a high purity sample of doubly isotopic 154Sm11B6 show no intrinsic excitations below the well-established 13 meV spin-exciton. The result of introducing impurities into a Kondo insulator is incompletely understood, but it is clear from our measurements that there is a systematic relationship between rare-earth impurities and metal-like properties in SmB6. The unconventional behaviour of samarium hexaboride has been difficult to explain in part because of differences between samples. Here the authors use gadolinium to exemplify that hard to avoid impurities introduce a low energy density of states that may explain earlier observations.
登录
查看更多内容
影响因子：
2.7
作者：
ALEKSEEV, PA;MIGNOT, JM;PADERNO, YB
通讯作者：
PADERNO, YB
影响因子：
3.7
作者：
Gorshunov, B;Sluchanko, N;Kunii, S
通讯作者：
Kunii, S
影响因子：
2.1
作者：
Gabáni, S;Flachbart, K;Sebek, J
通讯作者：
Sebek, J
影响因子：
2.7
作者：
KUNII, S;UEMURA, T;DATE, M
通讯作者：
DATE, M
影响因子：
8.6
作者：
Knolle, Johannes;Cooper, Nigel R.
通讯作者：
Cooper, Nigel R.