Study of long-range order of charges and/or spins in low-dimensional cuprates

低维铜氧化物中电荷和/或自旋的长程有序研究

• 批准号: 10440098
• 负责人: KOIKE Yoji
• 金额: $ 8.13万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10440098/
• 关键词: high-T_c superconductivity; 1; 8 anomaly; stripe; muon-spin-realxation; neutron scattering; transport properties; spin ladder; Sr_<14>Cu_<24>O_<41>; 単結晶育成; ホール効果; MSR; 非線形伝導

We have studied charge and/or spin order in the high-T_c cuprates and related cuprates, in order to obtain some informations on the mechanism of high-T_c superconductivity. The results obtained are as follows.1. We have discovered the so-called 1/8 anomaly, namely, the anomalous suppression of superconductivity at the hole concentration p=1/8 per Cu in the partially Zn-doped Bi-2212 cuprates as well as in the La-214 cuprates. We have also found from the muon-spin-relaxation measurements that the spin correlation is enhanced at low temperatures at p=1/8 in the Zn-doped Bi-2212 and Y-123 cuprates. Accordingly, it is concluded that the 1/8 anomaly is common to the high-T_c cuprates.2. We have discovered anomalous suppression of superconductivity and enhancement of the spin correlation at x=0.21 in La_<2-x>Sr_xCu_<1-y>Zn_yO_4. From the neutron scattering experiment of the single crystal with x=0.21 and y=0.01, we have observed incommensurate magnetic peaks around (π, π), which is similar to those observed at p=1/8. Accordingly, it is very likely that the dynamical stripe order of spins and holes is pinned by Zn, leading to the static stripe order and the suppression of superconductivity at x=0.21 as well as at p=1/8.3. From the above results, it is concluded that the stripe correlations of spins and holes exist in a wide range of hole concentration and that there is a possibility that they play an important role in the appearance of high-T_c superconductivity.4. We have studied the spin ladder cuprate Sr_<14>Cu_<24>O_<41> from the transport measurements, and concluded that holes are paired at low temperatures rather than form charge density wave. We have also found that the thermal conductivity due to spins is anomalously large in this system.

为了获得有关高-T_C超导性机制的一些信息，我们已经在高-T_C酸奶和相关的酸奶中研究了电荷和/或自旋顺序。获得的结果如下1。我们已经发现了所谓的1/8异常，即，在部分Zn掺杂的BI-2212 cuprates以及LA-214 Cuprates中，在孔浓度p = 1/8处的超导性异常抑制p = 1/8。我们还从Muon-Spin - 释放测量结果中发现，在Zn掺杂的BI-2212和Y-123 Cuprates中，在低温下，自旋相关性在p = 1/8时增强。据此，可以得出结论，高-T_C Cuprates的1/8异常是2。我们已经发现了在la_ <2-x> sr_xcu_ <1-y> zn_yo_4中x = 0.21处的超导性和增强自旋相关性的异常抑制。从X = 0.21和Y = 0.01的单晶的中子散射实验中，我们观察到（π，π）周围的不超高磁峰，这与在p = 1/8时观察到的磁峰相似。据此，旋转和孔的动态条纹顺序很可能被Zn固定，从而导致静态条纹顺序以及在X = 0.21以及p = 1/8.3处的超导性抑制。从以上结果得出结论，旋转和孔的条纹相关性存在于广泛的孔浓度中，并且它们可能在高-T_C超导性的外观中起重要作用。4。我们已经从运输测量值中研究了自旋梯子sr_ <14> cu_ <24> o_ <41>，并得出结论，在低温下而不是形成电荷密度波的孔配对。我们还发现，在该系统中，由于旋转引起的热导率是较大的。

项目成果

M.Akoshima: "On the 60K Plateau of Tc in Y_<1-x>Ca_xBa_2Cu_3O_<7-δ> in Relation to the 1/8 Problem" Journal of the Physical Society of Japan. 67・10. 3653-3654 (1998)

M.Akoshima：“关于Y_<1-x>Ca_xBa_2Cu_3O_<7-δ>中的60K高原与1/8问题的关系”日本物理学会杂志67・10 3653-3654（1998年）。 ）

K.Kubo: "Spin gap and hole pairing of Sr_<14-x>A_xCu_<24>O_<41> (A=Ca and La) single crystals studied by the erlectrical resistivity and thermal conductivity"Journal of Low Temperature Physics. 117・5/6. 1689-1693 (1999)

K.Kubo：“通过电阻率和热导率研究Sr_<14-x>A_xCu_<24>O_<41>（A=Ca和La）单晶的自旋间隙和空穴配对”《低温物理学杂志》117。・5/6。1689-1693（1999）

Y.Koike, M.Akoshima, T.Adachi, N.Kakinuma, T.Noji, Y.Ono, T.Nishizaki, N.Kobayashi, I.Watanabe and K.Nagamine.: "1/8 problems in the La-, Bi- and Y-based cuprates and new anomalies in the overdoped region of the La-based cuprate."International Journal of

Y.Koike、M.Akoshima、T.Adachi、N.Kakinuma、T.Noji、Y.Ono、T.Nishizaki、N.Kobayashi、I.Watanabe 和 K.Nagamine.：“La- 中的 1/8 问题

I.Watanabe: "Anomalous slowing down of Cu-spin fluctuations observed by muon spin relaxation to the Zn-substituted Bi_2Sr_2Ca_<1-x>Y_x (Cu_<1-y>Zn_y)_2 o_<8+S> system around-the hole concentration of 1/8 perCn"Physical Review B. 60・14. R9955-R9958 (1999)

I.Watanabe：“通过对 Zn 取代的 Bi_2Sr_2Ca_<1-x>Y_x (Cu_<1-y>Zn_y)_2 o_<8+S> 系统的 μ 子自旋弛豫观察到 Cu 自旋波动的异常减慢。 1/8 perCn“物理评论B.60・14浓度的孔。R9955-R9958（1999）

I.Watanabe, M.Aoyama, M.akoshima, K.Nishimaki, T.Kawamata, T.Adachi, Y.Koike, S.Ohira, W.Higemoto and K.Nagamine: "μSR study on the Cu-spin state in La_<2-x>Sr_xCu_<1-y>Zn_yO_4."International Journal of Modern Physics B. (in press).

I.Watanabe、M.Aoyama、M.akoshima、K.Nishimaki、T.Kawamata、T.Adachi、Y.Koike、S.Ohira、W.Higemoto 和 K.Nagamine：“Cu 自旋态的 μSR 研究La_<2-x>Sr_xCu_<1-y>Zn_yO_4。“国际现代物理学杂志 B.（出版中）。