Electronic states of alkali-doped CィイD260ィエD2 compounds : a NMR study

碱掺杂 C260D2 化合物的电子态：NMR 研究

• 批准号: 09640443
• 负责人: MANIWA Yutaka
• 金额: $ 2.05万
• 依托单位: TOKYO METROPOLITAN UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09640443/
• 关键词: CィイD260ィエD2; NMR; superconductor; Mott transition; antiferromagnet; metal-insulator transition; electronic state; 磁性

A systematic study of alkali-doped CィイD260ィエD2 compounds, AィイD23ィエD2CィイD260ィエD2 where A is a alkali metal, has been performed to clarify the electronic states, using nuclear magnetic resonance (NMR) technique. Main results are summarized as follows.1. The ィイD113ィエD1C-heperfine coupling constants have been determined in the superconducting AィイD23ィエD2CィイD260ィエD2.2. At, low temperatures (<100K), the enhancement of Korringa product, has been determined, which shows a weak antiferromagnetic correlation.3. Rising temperature and increasing lattice constant, the enhancement of Korringa product, increases. This was at atributed to the short electron mean free path in this system.4. Ammoniated AィイD23ィエD2CィイD260ィエD2 superconductors with expanded lattice constants show a "gap"-like behavior in the temperature dependence of spin-lattice relaxation time TィイD21ィエD2.5. It was shown that (NH3)K3C60 is described as a localized spin system in whole temperature studied (<300 K) and undergoes an antiferromagnetic transition at 45 K.6. From these results, it was strongly suggested that the metallic state of AィイD23ィエD2CィイD260ィエD2 is unstable to the local distortion around CィイD260ィエD2 molecules.

利用核磁共振（NMR）技术对碱掺杂C260D2化合物（其中A为碱金属）进行了系统研究，以阐明其电子态。主要结果总结如下： 1．已在超导中确定AD23D2CD260D2.2. 在低温（<100K）下，Korringa 积的增强已被确定，这显示出弱的反铁磁相关性。3. 温度升高和晶格常数增加，Korringa 积的增强增加。归因于该体系中电子平均自由程短。 4．具有扩展晶格常数的 AD23D2CD260D2 超导体在自旋晶格弛豫时间 TD21D2.5 的温度依赖性中表现出类似“间隙”的行为，结果表明 (NH3)K3C60 在整个研究温度 (<300) 中被描述为局域自旋系统。 K) 并在 45 处经历反铁磁转变K.6.从这些结果强烈表明AD23D2CD260D2的金属态对于CD260D2分子周围的局部变形不稳定。

项目成果

H. Shimizu: "NMR in silicon clathrate compounds NaィイD2xィエD2BaィイD2yィエD2SiィイD246ィエD2 and NaィイD2xィエD2SiィイD2136ィエD2"Synthetic Metals. 86. 2141-2142 (1997)

H. Shimizu：“硅笼形化合物 NaD2xD2BaiD2yD2SiD246D2 和 NaD2xD2SiD2136D2 中的 NMR”合成金属。 86. 2141 -2142 (1997)

Yutaka Maniwa: "Development of Superstructure in Potassium-Loaded Zeolite LTA, KィイD2xィエD2-KィイD212ィエD2SiィイD212ィエD2AlィイD212ィエD2OィイD248ィエD2"J. Phys. Soc. Jpn.. 68. 2902-2905 (1999)

Yutaka Maniwa：“钾负载沸石 LTA 的上部结构的开发，KD2xD2-KD212D2SiD212D2AlD212D2OD248D2”Jpn. 68. 2902-2905 (1999)

X.Chen: "Preparation of Rb_3C_<60> Utilizing Room Temperature Solubilization in・・・" to be appeared in Chemistry of Materials.

X.Chen：“利用室温溶解在……中制备 Rb_3C_<60>”将发表在《材料化学》上。

Y.Maniwa: "^<13>CNMR and static magnetics susceptibility in C_<60> superconductors"Phys.Rev.. B58. 11603-11606 (1998)

Y.Maniwa：“C_<60>超导体中的^ 13 CNMR和静磁化率”Phys.Rev..B58。

Y.Maniwa: "^<13>C-NMR and static magnetic susceptibility in C_<60> superconductors" Phys.Rev.B58. 11603-11606 (1998)

Y.Maniwa：“C_<60>超导体中的^ 13 C-NMR和静磁化率”Phys.Rev.B58。