Structural Difference in Superconductive and Nonsuperconductive Bi-S Planes within Bi4O4Bi2S4 Blocks
Structural Difference in Superconductive and Nonsuperconductive Bi-S Planes within Bi4O4Bi2S4 Blocks
复制标题
Bi4O4Bi2S4 块内超导和非超导 Bi-S 平面的结构差异
DOI：
10.1021/acs.inorgchem.5b01919
复制
发表时间：
2015
影响因子：
4.6
通讯作者：
Kiyoharu Tadanaga
中科院分区：
文献类型：
--
作者：
Akira Miura;Yoshikazu Mizuguchi;Tsuyoshi Sugawara;Yongming Wang;Takahiro Takei;Nobuhiro Kumada;Eisuke Magome;Chikako Moriyoshi;Yoshihiro Kuroiwa;Osuke Miura;Kiyoharu Tadanaga
采用同步辐射X射线衍射、拉曼光谱和透射电子显微镜（TEM）研究了常压和高压加热合成的Bi 4 O 4S 3粉体的结构与超导电性之间的关系。常压下合成的Bi 4 O 4S 3粉体在低于104.5K的温度下表现出强的超导（抗磁）信号和零电阻率，而高压法合成的Bi 4 O 4S 3粉体在低于2K的温度下表现出低强度信号。后者Bi 4 O 4S 3粉末在环境压力下的进一步退火导致发展的强信号和零电阻率。所有Bi 4 O 4S 3相的晶体结构均由Bi 4 O 4 Bi 2S 4块体组成，其中包含Bi-S层和夹在Bi 4 O 4 Bi 2S 4块体之间的阴离子，但检测到微小的结构差异。对无定形和无定形的Bi 4 O 4S 3样品的结构进行了比较，结果表明无定形的Bi 4 O 4S 3相具有较小的晶格参数。Bi 4 O 4S 3相的平均结构特征为Bi-S面较短且弯曲度较小。拉曼光谱检测到S-O键的振动，这可以归因于夹心阴离子，如SO 42-。透射电镜观察发现，在Bi_4O_4S_3相中存在层错，表明平均结构的局部起伏。根据杂质相、Bi_4O_4Bi_2S_4块内Bi-S平面的px和pyorbitals的增强杂化、平均结构的局部涨落、与夹在Bi_4O_4Bi_2S_4块之间的可疑阴离子有关的组成偏差以及富集载流子浓度抑制电荷密度波态的可能性，讨论了所观察到的Bi_4O_4S_3的超导电性。
The relationship between the structure and superconductivity of Bi4O4S3powders synthesized by heating under ambient and high pressures was investigated using synchrotron X-ray diffraction, Raman spectroscopy, and transmission electron microscopy (TEM) observation. The Bi4O4S3powders synthesized under ambient pressure exhibited a strong superconductivity (diamagnetic) signal and zero resistivity below ∼4.5 K, while the Bi4O4S3powder synthesized by the high-pressure method exhibited a low-intensity signal down to 2 K. Further annealing of the latter Bi4O4S3powder under ambient pressure led to the development of a strong signal and zero resistivity. The crystal structures of all Bi4O4S3phases consisted of Bi4O4Bi2S4blocks including a Bi–S layer and anion(s) sandwiched between Bi4O4Bi2S4blocks, but minor structural differences were detected. A comparison of the structures of the superconductive and nonsuperconductive Bi4O4S3samples suggested that the superconductive Bi4O4S3phases had slightly smaller lattice parameters. The average structures of the superconductive Bi4O4S3phases were characterized by a slightly shorter and less bent Bi–S plane. Raman spectroscopy detected vibration of the S–O bonds, which can be attributed to sandwiched anion(s) such as SO42–. TEM observation showed stacking faults in the superconductive Bi4O4S3phases, which indicated local fluctuation of the average structures. The observed superconductivity of Bi4O4S3was discussed based on impurity phases, enhanced hybridization of the pxand pyorbitals of the Bi–S plane within Bi4O4Bi2S4blocks, local fluctuation of the average structures, compositional deviation related to suspicious anion(s) sandwiched between Bi4O4Bi2S4blocks, and the possibility of suppression of the charge-density-wave state by enriched carrier concentrations.