Effects of Y substitution on the electronic structure and charge dynamics of SmS
Effects of Y substitution on the electronic structure and charge dynamics of SmS
复制标题
Y取代对SmS电子结构和电荷动力学的影响
DOI：
10.1103/physrevb.100.245143
复制
发表时间：
2019
影响因子：
3.7
通讯作者：
Takenaka K.
中科院分区：
文献类型：
--
作者：
Yokoyama Y.;Hasegawa H.;Mizuno Y.;Asai D.;Okamoto Y.;Suzuki H. S.;Takehana K.;Imanaka Y.;Takenaka K.
通过对单晶体的系统反射率测量，研究了Y掺杂对电子态的影响。虽然Y掺杂剂掺杂到能带上的电子立即实现了金属态，但电荷动力学不服从简单的Drude响应，光谱强度在中红外区域被压缩。相反的压力诱导的情况下，金属相出现在一定的组成区域之前达到价态转变。电子掺杂使费米能级上移。因此，该带必须与弱色散带重叠更深，比在压力诱导的情况下，以达到价转变，这可以解释的稳定性的二价相的掺杂系统比在压力诱导的情况下更高的温度。目前的光学研究为我们提供了一个策略，硫缺乏可能会增加负热膨胀在这个系统中的操作温度。
Evolution of the electronic state by Y doping was explored by optical conductivity covering a wide energy and compositional region deduced from systematic reflectivity measurements ofsingle crystals. Although electrons doped onto theband by Y dopants immediately realize a metallic state, the charge dynamics do not obey a simple Drude response and the spectral intensity is condensed in the mid-infrared region. Contrary to the pressure-induced case, a metallic phase appears in a certain compositional region before reaching the valence transition. The Fermi level is shifted upwards by electron doping. Therefore, theband must overlap with the weakly dispersiveband more deeply than in the pressure-induced case to reach the valence transition, which can explain the stability of the divalent phase up to higher temperatures in the doped system than in the pressure-induced case. The present optical study provides us with a strategy that sulfur deficiency might increase operating temperature of negative thermal expansion in this system.