Fablication and electrical properties of transition metal sulfide-heterocyclic compounds molecular crystals

将过渡金属(钛)和硫(S)与少量添加剂(锆、钒、铁、锡)粉末混合，在石英玻璃管中反应，得到几种类型的钛(Ti)和硫(Gt)；M_xS_2。对烧结体进行了晶体结构分析和磁化强度测量，并通过Rietveld分析对其晶体结构进行了细化，确认这些材料为抗磁/金属材料。通过与吡咯、吡啶、吡咯烷、哌嗪、咪唑等杂环化合物水蒸气反应生成TiS_2或NbS_2晶体，得到过渡金属硫化物和杂环化合物分子晶体。在TiS_2中，分子晶体表现为MS_2二级插层，而NbS_2为一级插层。该分子晶体是由有机物插入拉开层间距离的结构，电导率测试表明该分子晶体还具有半导体性质。对这些分子晶体进行了能带结构计算，结果表明这些分子晶体为间接过渡型半导体，与实验结果基本一致。一种TiS_2-杂环化合物分子晶体的电阻在140K左右迅速下降(由于发表不足，本文省略了详细的描述)，这种异常在目前的VSM磁化测量中还没有被识别出来进行后续研究，因此有必要对分子晶体的电导异常进行更多的研究。

Transition metal (Ti) and sulfur (S) with small amount of additives (Zr, V, Fe, Sn) powder was mixed and reacted in silica glass tube, and several types of Ti_<1-x>M_xS_2 were obtained. Crystal structure analysis and magnetization measurement were carried out for sintered body, and the crystal structure was refined by Rietveld analysis, and it was confirmed that these materials were the diamagnetic/ metallic material. Further, transition metal sulfide and heterocyclic compound molecular crystals were produced by reacting with heterocyclic compound steam such as pyrrole, pyridine, pyrrolidine, piperazine, and imidazole into TiS_2 or NbS_2 crystal. In TiS_2, the molecular crystal showed the MS_2 intercalation in second order; however, NbS_2 in first order was synthesized. This molecular crystal was the structure in which interlayer distance opened by the organic substance insertion, and anyway also showed the semiconductor property as shown by the electrical conductivity measurement. The band structure calculation was done, it became a result that these molecular crystals were semiconductors of the indirect transition type, and it agreed with the experimental result almost. The electrical resistance rapidly decreased for some kind of TiS_2-heterocyclic compound molecular crystal (the description detailed is omitted on this paper because of under publishing) around 140 K. Such abnormality carries out the follow-up study without recognizing in the magnetization measurement by VSM, at present.It is necessary to carry out the research more and more on electric conductivity abnormality of the molecular crystal.