Electronic Structure of Rare-Earth Sesquisulfide Crystals
Electronic Structure of Rare-Earth Sesquisulfide Crystals
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稀土倍半硫化物晶体的电子结构
DOI：
10.1063/1.1712397
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发表时间：
1967
期刊：
影响因子：
--
通讯作者：
J. B. Gruber
中科院分区：
文献类型：
--
作者：
J. Henderson;M. Muramoto;E. Loh;J. B. Gruber
用氩等离子体焰熔法和坩埚下降法生长了R_2S_3（R = Dy、Gd、Nd和Y）单晶。本文讨论了R_2O_3原料的提纯、R_2S_3化合物粉末的合成与分析、晶体生长、单晶的分析测定、电阻率和300° ~ 1300°K热电功率系数的测量。电测量表明，与以前的报告相比，稀土碲化物和硒化物的高度简并的半导体行为与ρ和α随温度的增加。通过粉末的反射光谱、单晶的吸收光谱和单晶的磁化率测量，分别证实了稀土离子以三价态存在和不存在二价离子。这些材料是不寻常的，因为它们是半导体，稀土离子的（4f）n能级跨越梯形带隙。
Single crystals of R2S3, R = Dy, Gd, Nd, and Y, have been grown by flame fusion in an argon plasma torch and by the Bridgman technique. The purification of R2O3 starting materials, synthesis and analysis of compound powders R2S3, crystal growth, analysis to determine if single crystals are produced, and measurement of electrical resistivity and thermoelectric power coefficient from 300° to 1300°K and discussed. The electrical measurements indicate highly degenerate semiconductor behavior with ρ and α increasing with temperature in contrast with previous reports for rare-earth tellurides and selenides. The presence of the rare-earth ions in their trivalent state and the absence of divalent ions have been confirmed independently by reflectance spectra from powders, by absorption spectra of single crystals, and by measurement of magnetic susceptibility of single crystals. The materials are unusual because they are semiconductors with the (4f)n levels of the rare-earth ions spanning the bandgap in ladderlike ...