Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale Aldo Moro 2, 00185 Roma, Italy.
J Phys Condens Matter. 2011 Oct 26;23(42):425701. doi: 10.1088/0953-8984/23/42/425701.
The local structure of Fe(Se, S)(1-x)Te(x) ternary (11-type) chalcogenides has been studied by temperature dependent Fe K-edge extended x-ray absorption fine structure measurements. We find that the Fe-Se and Fe-Te distances in ternary FeSe(1-x)Te(x) are closer to the respective distances in the binary systems, revealing significant divergence of the local structure from the average one. The mean square relative displacements show a systematic change with Te content, consistent with bond relaxation in the inhomogeneous ternary phases. Also, the Fe-Te and Fe-S distances in the FeS(0.2)Te(0.8) ternary system are found to be different in the crystallographically homogeneous structure. The observed features are characteristic of ternary random alloys, suggesting that a proper consideration should be given to the atomic distribution for describing the complex electronic structure of these multi-band Fe-based chalcogenides.
通过温度依赖的 Fe K 边扩展 X 射线吸收精细结构测量，研究了 Fe(Se, S)(1-x)Te(x)三元（11 型）硫属化物的局域结构。我们发现三元 FeSe(1-x)Te(x)中的 Fe-Se 和 Fe-Te 距离更接近二元体系中的相应距离，表明局域结构与平均结构明显偏离。平均平方相对位移随 Te 含量呈系统变化，与非均匀三元相中的键弛豫一致。此外，在结构上同质的 FeS(0.2)Te(0.8)三元体系中，Fe-Te 和 Fe-S 距离也有所不同。观察到的特征是三元随机合金的特征，表明在描述这些多带 Fe 基硫属化物的复杂电子结构时，应该适当考虑原子分布。
