Exfoliation of a layered high-T_c superconductor

层状高温超导体的剥离

基本信息

批准号：
11640331
负责人：
SHAMOTO Shin-ichi
金额：
$ 2.24万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640331/
关键词：
superconductor layered nitride exfoliation inorganic monolayer

项目摘要

In the present research, exfoliation of a layered high-T_c superconductor Li_x (THF)_yHfNCl has been studied, where organic solvents such as pyridine, dimethylsulfoxide, N,N-dimethylformamide, and N-methylformamide were used to solve the Li_x(THF)_yHfNCl sample with large interlayer distance, i.e., about 1.87 nm. Unfortunately, our Li_x(THF)_yHfNCl sample (x〜0.5) has never been dissolved in these solvents. On the other hand, structures and physical properties on related honeycomb lattice superconductors, such as Na_<0.29>HfNCl and Li_<0.19>ZrNBr, have also been studied. Structures of related superconductors, Na_<0.29>HfNCl and Li_<0.19>ZrNBr, have been determined successfully by Rietveld analysis using neutron diffraction data. We are the only research group that has succeeded in determining the structures of these alkali metal intercalated superconducting samples, which are unstable in air. Inelastic neutron scattering study of Na_xHfNCl revealed that the phonon density of states (PDOS) at several energies much higher than the superconducting energy gap increased remarkably, which was the similar behavior to high-T_c cuprates, e.g., La_<1.85>Sr_<0.15>CuO_4 and YBa_2Cu_3O_7. Recent neutron scattering studies indicate that these increases of PDOS relating to phonon dispersion anomaly would be due to the existence of dynamical charge density wave (DCDW). It suggests that DCDW might be a common characteristic among high-T_c superconductors with some electronic instability including Ba_<1-x>K_xBiO_3, which seems to be quite different with one another in terms of spin fluctuation.

在本研究中，已经进行了层状高-T_C超导体LI_X（THF）_yhfnCl的去角质，其中有机溶液（例如吡啶，二甲基硫代氧化物，N，N-二甲基甲基甲酰胺，N-二甲基甲酰胺，N-甲基甲基）和N-甲基形的n-甲基甲酰胺用于li_x（thff）（thff）（I. NM。不幸的是，我们的li_x（THF）_yhfncl样品（x〜0.5）从未溶解在这些解决方案中。另一方面，还研究了相关蜂窝晶格超导体（例如Na_ <0.29> HFNCL和LI_ <0.19> Zrnbr）上的结构和物理性能。相关超导体的结构，Na_ <0.29> HFNCL和LI_ <0.19> Zrnbr的结构已通过使用中子衍射数据成功地通过Rietveld分析成功确定。我们是唯一成功地确定这些碱金属插入超导样品的结构的研究小组，这些样品在空气中是不稳定的。 NA_XHFNCL的非弹性中子散射研究表明，状态的声子密度（PDOS）比超导能量差距高得多，这是与高-T_C Cuprates相似的行为，例如La__ <1.85> SR_ <1.85> SR_ <0.15> <0.15> cuo_4 and yba__2cu_2cu_3o_3o。最近的中子散射研究表明，与声子分散异常有关的PDO的增加将是由于存在动态电荷密度波（DCDW）所致。这表明DCDW可能是具有某些电子不稳定性的高-T_C超导体中的共同特征，包括BA_ <1-x> k_xbio_3，在自旋波动方面，这似乎彼此之间有很大不同。