^<13>C-NMR Study of the Organic Superconductor near the Superconductor-Insulator Phase Boundary

^13C-NMR研究超导体-绝缘体相界附近的有机超导体

• 批准号: 14540316
• 负责人: KAWAMOTO Atsushi
• 金额: $ 2.3万
• 依托单位: Hokkaido University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540316/
• 关键词: ^<13>C-NMR; κ-(BEDT-TTF)_2Cu[N(CN)_2]Br; strong correlated etectorn system; field-induced metal-insulator transition; Knight-shift; the spin-lattice relaxation rate; phase separation; partially deuteraion; 超伝導; BEDT-TTF; 有機超伝導体; 反強磁性

^<13>C-NMR study on non-deulerated and partially deuterated κ-(BEDT-TTF)_2Cu[N(CN)_2]Br is reported, where BEDT-TTF is bis(ethylenedithio)tetra-thiafulvalene. By using the BEDT-TTF molecule having ^<13>C-enriched on only one side of the central carbon sites, we could estimate the density of states from the Knight-shift and the spin-lattice relaxation rate. Although the reduced mass effect predicted from the specific heat measurement was not observed in the ^<13>C-NMR, the melal-to-anliferromagnetic phase transition was observed with the phase separation around 18K on the half-deuterated κ-(BEDT-TTF)_2Cu[N(CN)_2]Br under a high magnetic field. Such a transition does not occur under a zero or low field on the **lf-deuterated sal. These results suggest a first order field-induced metal-insulator transition. These findings can explain the complex phenomena near the phase boundary under a high magnetic field. We also found that the phase separation is observed at around T^* with the applied field parallel to the conducting layer, unlike partially deuterated κ-(BEDT-TTF-d[n,n])_2Cu[N(CN)_2]Br. The former result suggests the field induces AF transition. the latter result suggests there is the field direction dependence of the M-1 phase separation behavior in κ-(BEDT-TTF-d[4,4])_2Cu[N(CN)_2]Br.

^ 报道了非氘化和部分氘化的κ-(BEDT-TTF)_2Cu[N(CN)_2]Br的13C-NMR研究，其中BEDT-TTF是双(亚乙二硫)四硫富瓦烯。通过使用仅在中心碳位点的一侧富集^ 13 C的BEDT-TTF分子，我们可以根据奈特位移和自旋晶格弛豫率估计态密度。虽然在^ 13 C-NMR中没有观察到由比热测量预测的质量减少效应，但在高磁场下半氘化κ-(BEDT-TTF)_2Cu[N(CN)_2]Br上观察到金属到反铁磁的相变，并在18K左右发生相分离。这种转变不会在**1-氘代盐的零场或低场下发生。这些结果表明存在一阶场诱导金属-绝缘体转变。这些发现可以解释高磁场下相界附近的复杂现象。我们还发现，与部分氘化的 κ-(BEDT-TTF-d[n,n])_2Cu[N(CN)_2]Br 不同，在 T^* 附近观察到相分离，施加的场平行于导电层。前一个结果表明电场会引起 AF 转变。后一个结果表明 κ-(BEDT-TTF-d[4,4])_2Cu[N(CN)_2]Br 中的 M-1 相分离行为存在场方向依赖性。

项目成果

K.Ichimura, et al.: "STM Spectroscopy on Partially Deuterated κ-(BEDT-TTF)_2Cu[N(CN)_2]Br"Synthetic Metals. 137. 1229-1230 (2003)

K. Ichimura 等人：“部分氘化 κ-(BEDT-TTF)_2Cu[N(CN)_2]Br 合成金属的 STM 光谱”137. 1229-1230 (2003)

A.Kawamoto, et al.: "Phase control of κ-(BEDT-TTF)_2Cu[N(CN)_2]Br by partial deuteration"Synthetic Metals. 133-134. 123-124 (2003)

A. Kawamoto 等人：“通过部分氘化对 κ-(BEDT-TTF)_2Cu[N(CN)_2]Br 进行相控制”，《合成金属》133-134 (2003)。

J.Sasaki.A.Kawamoto, K.Kumagai: "Magnetic Properties of the alloy of κ-(BEDT-TIF)_<2(1-X)>(BEDSe-TIF)_<2X>Cu[N(CN)_2]Br"Synthetic Metals. 137. 1249-1250 (2003)

J.Sasaki.A.Kawamoto、K.Kumagai：“κ-(BEDT-TIF)_<2(1-X)>(BEDSe-TIF)_<2X>Cu[N(CN) 合金的磁性_2]Br“合成金属。137。1249-1250（2003）

Ichimura, K: "STM spectroscopy on partially deuterated κ-(BEDT-TTF)_2 Cu[N(CN)_2]Br"Synthetic Metals. 137. 1229-1230 (2003)

Ichimura, K：“部分氘化 κ-(BEDT-TTF)_2 Cu[N(CN)_2]Br”合成金属的 STM 光谱。137. 1229-1230 (2003)

J.Sasaki, et al.: "Magnetic Properties of the alloy of □-(BEDT-TTF)_<2(1-X)>(BEDSe-TTF)_<2X>Cu[N(CN)_2]Br"Synthetic Metals. 137. 1249-1250 (2003)

J.Sasaki 等人：“□-(BEDT-TTF)_<2(1-X)>(BEDSe-TTF)_<2X>Cu[N(CN)_2]Br 合金的磁性”合成金属。137。1249-1250（2003）