Lattice Instability in High-Temperature Superconductors

高温超导体中的晶格不稳定性

基本信息

批准号：
08044090
负责人：
FUJITA Toshizo
金额：
$ 3.33万
依托单位：
HIROSHIMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1996
资助国家：
日本
起止时间：
1996 至无数据
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08044090/
关键词：
high-temperature superconductors single crystal lattice instability neutron scottering de Haas van Alphen effect Fermi surface ドハース・ファン・アルフェン効果

项目摘要

In the vicinity of the doping level and the temperature range where the high-temperature superconductivity appcars, materials often encounter the lattice instability. From our acoustic study, the lattice instability and supercondueting transition are suggested to compete with each other in La_<2-x>Sr_xCuO_4 (LSCO). The aim of this research project is to inverstigatethe relation between the lattice instability and the superconductivity in LSCO and the reference material Sr_2RuO_4 (SRO). In collaboratin with a French group at Saclay, we (Japanese group) performed neutron experiments on our single-crystalline samples of LSCO and SRO.For SRO,we collaborated also with a British group at Cambridge on the deHaas van Alphen (dHvA) experiments to map the Fermi surface of SRO.Our works can be summarized as follows.1.We grew high-quality single crystals of LSCO,Nd-doped LSCO (LNSOC) and SRO.Part of the crystals were used for the X-ray diffraction, ultrasonic experiments, specific heat measurement … More s, dilatometry and measurements of transport coefficients. Another part of the crystals were sent to Saclay for the neutron experiments and some SRO crystals were used at Cambridge for the dHvA experiments.2.We obtained an evidence suggesting the stripe structure in LNSCO similar to what has been reported by Tranquada et al.But we should be careful enough to wait for our definite conclusion until we know the influence of lattice imperfection on the structure. We succeeded in analyzing the lattice structure of SRO in detail, the result of which has been published in Physica C.3.We could determine the Fermi surface for SRO from the dHvA experiment, which allowed us to discuss quantitatively the transport properties as well as the electronic speific heat. The result and discussion are published in four pieces of our recent papers.4.We also obtained various new findings on the nonmetallic out-of-plane conduction, the splitting of the density of states near the Fermi level due to the 1/8 anomaly in LNBCO as well as on the possible p-wave pairing in SRO. Less

在掺杂水平的附近和高温超导性Appcars的温度范围内，材料经常遇到晶格不稳定性。从我们的声学研究中，建议在LA__ <2-x> sr_xcuo_4（LSCO）中相互竞争，晶格不稳定性和超模型过渡。该研究项目的目的是消除LSCO中的晶格不稳定性与超导性之间的关系和参考材料SR_2RUO_4（SRO）。我们（日本小组）在与法国小组合作，在我们的单晶样品中进行了中子实验，我们还与Sro.sro的单晶样品进行了合作，我们还与剑桥的Dehaas van Alphen（dhva）实验的剑桥与一个英国集团合作，以绘制Sro.s sro.s的fermi surrip。 LSCO，ND掺杂的LSCO（LNSOC）和SRO。晶体的部分用于X射线衍射，超声波实验，特定的热量测量……更多S，扩张法和运输系数的测量值。 Another part of the crystals were sent to Saclay for the neutron experiments and some SRO crystals were used at Cambridge for the dHvA experiments.2.We obtained an evidence suggesting the stripe structure in LNSCO similar to what has been reported by Tranquada et al.But we Should be careful enough to wait for our defined conclusion until we know the influence of lattice imperfection on the structure.我们成功地详细分析了SRO的晶格结构，其结果已在Physica C.3中发表。3。我们可以从DHVA实验中确定SRO的费米表面，这使我们能够定量地讨论传输性能以及电子特异性热量。结果和讨论发表在我们最近的四篇论文中。4。我们还获得了有关非金属平面外传导的各种新发现，由于LNBCO中的1/8异常以及SRO中可能的P-Wave配对，由于FERMI水平附近的状态密度分裂。较少的