Relation between charge order and Nernst effect

电荷顺序与能斯特效应的关系

• 批准号: 21740248
• 负责人: FUJII Takenori
• 金额: $ 2.83万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Young Scientists (B)
• 财政年份: 2009
• 资助国家: 日本
• 起止时间: 2009 至 2011
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-21740248/
• 关键词: 高温超伝導; 銅酸化物高温超伝導体; ネルンスト効果; 電荷秩序; ストライプ秩序; 量子臨界点; 圧力効果; 圧力下ネルンスト測定

e have precisely measured the Nernst effect in Nd-doped La_<2-x> Sr_xCuO_4 single crystals with controlling the strength of the stripe order. We found that the onset temperature T_onset, where the Nernst signal starts increasing, does not change conspicuously in spite of Nd-doping. At low temperatures, on the other hand, the absolute value of the Nernst signal is strongly suppressed in accordance with the strength of the stripe order. These results imply that the fluctuation of(charge) stripe order enhances the Nernst signal below T_onset at high temperatures, and then the stripe order enhanced by Nd-doping suppresses the superconducting fluctuation to reduce the Nernst signal at low temperatures. We also observed an increase of the Nernst signal below the charge order temperature T_ch which is observed in diffraction measurement.

我们通过控制条纹序的强度，精确测量了 Nd 掺杂 La_2-xSr_xCuO_4 单晶的能斯特效应。我们发现，尽管有 Nd 掺杂，能斯特信号开始增加的起始温度 T_onset 并没有明显变化。另一方面，在低温下，能斯特信号的绝对值根据条纹顺序的强度而被强烈抑制。这些结果表明，高温时（电荷）条带序的波动增强了T_onset以下的能斯特信号，而Nd掺杂增强的条带序抑制了超导波动，从而降低了低温下的能斯特信号。我们还观察到能斯特信号在衍射测量中观察到的电荷有序温度 T_ch 以下有所增加。