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Single Crystal Growth of Double Honeycomb Lattice Superconductor Related Materials

双蜂窝晶格超导相关材料的单晶生长

基本信息

批准号：
15340108
负责人：
SHAMOTO Shin-ichi
金额：
$ 10.3万
依托单位：
Japan Atomic Energy Agency (2004-2005)Tohoku University (2003)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15340108/
关键词：
Superconductivity Double honeycomb lattice Layered nitride

项目摘要

Structural study of double honeycomb lattice related materials such as Na_<0.9>Zr_2N_2S_<1.5>, Na_<0.85>Hf_2N_2S_<1.5>, Zr_2N_2S, and Hf_2N_2S has been performed by using X-ray powder diffraction data. As for Zr_2N_2S, and Hf_2N_2S, some reflection peaks such as -101 and 10-3 were broadened significantly, suggesting the intergrowth of α-M_2N_2S and β-M_2N_2S phases. This is a typical characteristic for two-dimensional compounds due to stacking faults. It indicates that the energy difference in stacking between α-M_2N_2S and β-M_2N_2S phases is very small. The structural analysis for these compounds has been carried out without these broad peaks. Based on the results, we estimated the band widths for these compounds. These estimated band widths were narrower than the band width of Na_<0.28>HfNCl, which had been the narrowest band width in any double honeycomb lattice compounds so far, suggesting large electron density of states. These band widths, however, do not correspond to our previous expectation. That is, the smaller the valence difference of two anions relative to the cation valence is, the narrower the band width is. The alkali metal intercalated HfNCl and ZrNCl superconductors exhibit wider band widths than the pristine compounds. So, the present double honeycomb lattice compounds may also show wider band widths after electron carrier doping. Carrier doped YOCl compounds have narrower band widths than the HfNCl and ZrNCl superconductors. It suggests that strong carrier localization due to the narrow band width plays an important role for the insulating property even with large number of carrier density. In these insulators, it is interesting to study the localized spin behavior with strong pairing interaction. This is the most important subject in the remaining research works about the present double honeycomb lattice compounds.

本文用X射线粉末衍射数据研究了Na_<0.9>Zr_2N_2S_<1.5>、Na_<0.85>Hf_2N_2S_<1.5>、Zr_2N_2S和Hf_2N_2S等双蜂窝晶格材料的结构。Zr_2N_2S和Hf_2N_2S的-101和10-3反射峰明显展宽，表明α-M_2N_2S和β-M_2N_2S相共生。这是由于堆垛层错而导致的二维化合物的典型特征。结果表明，α-M_2N_2S和β-M_2N_2S相的堆垛能差很小。对这些化合物进行了结构分析，没有这些宽峰。根据这些结果，我们估计了这些化合物的带宽。这些估算的能带宽度比Na_ HfNCl的能带宽度要窄<0.28>，而Na_ HfNCl的能带宽度是迄今为止在所有双蜂窝晶格化合物中最窄的，表明其具有较大的电子态密度。然而，这些带宽并不符合我们先前的预期。也就是说，两个阴离子相对于阳离子的化合价的化合价差越小，带宽度越窄。碱金属插层HfNCl和ZrNCl超导体具有比原始化合物更宽的带宽。因此，本发明的双蜂窝晶格化合物在电子载流子掺杂后也可以显示更宽的带宽。载流子掺杂的YOCl化合物具有比HfNCl和ZrNCl超导体更窄的带宽。这表明，由于窄带宽的强载流子局域化的绝缘性能起着重要的作用，即使有大量的载流子密度。在这些绝缘体中，研究具有强对相互作用的局域自旋行为是有趣的。这是目前双蜂窝晶格化合物研究工作中最重要的课题。

项目成果

期刊论文数量（37）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Phonon anomaly on Na_xHfNCl superconductors with T_c=22K

T_c=22K 的 Na_xHfNCl 超导体上的声子异常

DOI：
发表时间：
2004
期刊：
J.Neutron Research 12・4
影响因子：
0
作者：
Tomitsugu Taguchi;Naoki Igawa;Hiroyuki Yamamoto;Shin-ichi Shamoto;Shiro Jitsukawa;S.Shamoto et al.;S.Shamoto et al.;J.-H.Chung et al.;T.Yokoya et al.;S.Shamoto et al.
通讯作者：
S.Shamoto et al.

Mater.Res.Soc.Symp.Proc.Q6