Interaction between novel vortices in nano-structured superconductors

纳米结构超导体中新型涡旋之间的相互作用

• 批准号: 18540354
• 负责人: KATO Masaru
• 金额: $ 2.45万
• 依托单位: Osaka Prefecture University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2006
• 资助国家: 日本
• 起止时间: 2006 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18540354/
• 关键词: Superconducting materials and devices; Interaction between magnetic fluxes; Nano superconductivity; Nano-materials; Theory of condensed matters

A simulation method for d-dot systems, which are composite structures of d- and s-wave superconductors, are developed, using two-components Ginzburug-Landau equations. Using this simulation, it is shown that interaction between two d-dot's becomes novel one and it depends on the distance and directions between them. Especially, fusion of two half-quantum fluxes occurs in short distance and it affects the interaction. Using this interaction, novel superconducting logic gates are proposed. And their operation is confirmed by the numerical simulations. Also it is shown that their operation speed is order of pico-second and d-dot logic circuit become good candidate for a computer of the next generation.A simulation method for investigation of microscopic properties of arbitrary shaped nano-sized superconductors is developed using the Bogoliubov-de Gennes equations. Using this method, interaction between two vortices is investigated. And a vortex molecule state is found. The quasi-particles … More around it show molecular orbital-like states. This property affect the interaction, which was believe to be purely repulsive from the phenomenological theory. This interaction affects the vortex configuration, in which the distance of vortices is rather short. Also quasi-particle structure around a giant vortex, which is peculiar to the nano-sized superconductors, is found to be different from that of a singly quantized vortex. Using similar method, it is shown that nano-sized anisotropic superconductors. have the modulated quasi-particle states in side of the energy gap, because of the confinement of the nodal states in the energy gap of anisotropic superconductors. These properties can be confirmed by the scanning tunneling spectroscopy experiment.Simulation method for dynamics of vortices in the superconducting networks is developed, by using combined one-dimensional and two-dimensional finite element method. Using this simulation method, it is shown that asymmetric finite superconducting networks shows ratchet effect, i.e. the vortex motion in these networks under external A.C. current causes D.C. voltage.Also vortex structure of random superconducting networks, which are models of porous superconductors, is investigated. Because of anomalous vortex pinning, which comes from their randomness, the transition temperature becomes low and vortices show peculiar structure. This result shows that such porous superconductors are good candidate for high Jc superconducting materials. Less

使用二元 Ginzburug-Landau 方程开发了 d 点系统（d 波和 s 波超导体的复合结构）的模拟方法。通过该模拟，结果表明两个 d 点之间的相互作用变得新颖，并且取决于它们之间的距离和方向。特别是，两个半量子通量的聚变发生在短距离内，并且影响相互作用。利用这种相互作用，提出了新型超导逻辑门。他们的操作得到了数值模拟的证实。还表明它们的运行速度为皮秒量级，d点逻辑电路成为下一代计算机的良好候选者。利用Bogoliubov-de Gennes方程开发了一种研究任意形状纳米尺寸超导体微观特性的模拟方法。使用这种方法，研究两个涡旋之间的相互作用。并发现了涡旋分子态。它周围的准粒子显示出类似分子轨道的状态。这种性质影响相互作用，这被认为是现象学理论纯粹排斥的。这种相互作用会影响涡旋构型，其中涡旋的距离相当短。此外，纳米超导体所特有的巨型涡旋周围的准粒子结构也被发现与单量子化涡旋不同。采用类似的方法，表明了纳米尺寸的各向异性超导体。由于节点态被限制在各向异性超导体的能隙中，因此在能隙一侧具有调制的准粒子态。这些性质可以通过扫描隧道光谱实验来证实。采用一维和二维相结合的有限元方法，建立了超导网络中涡流动力学的模拟方法。利用该模拟方法，表明非对称有限超导网络表现出棘轮效应，即在外部交流电流作用下，这些网络中的涡旋运动引起直流电压。此外，还研究了多孔超导体模型随机超导网络的涡旋结构。由于其随机性产生的反常涡旋钉扎，其转变温度变低，涡旋呈现出特殊的结构。这一结果表明，这种多孔超导体是高 Jc 超导材料的良好候选者。较少的

项目成果

MgB2中性子検出器の開発と熱緩和シミュレーション

MgB2中子探测器研制及热弛豫模拟

• 发表时间: 2007
• 作者: 西川 正利;藤田 賢文;新井 康平;三木 茂人;島 影尚;王 鎮;佐藤 和郎;四谷 任;岡安 悟;片桐 政樹;森井 幸生;北條 喜一;新村 信雄;町田 昌彦;加藤 勝;石田 武和
• 通讯作者: 石田 武和

Vortex (particle) and antivortex (hole) doping into superconducting network

涡旋（粒子）和反涡旋（空穴）掺杂到超导网络中

• 发表时间: 2007
• 期刊: Physica C 460-462
• 作者: T. Ishida;M. Shimizu;Y. Matsushima;M. Hayashi;H. Ebisawa;O. Sato;M. Kato;K. Sato;T. Yotsuya
• 通讯作者: T. Yotsuya

Vortex motion in mesoscopic superconducting plate with holes II

带孔介观超导板中的涡运动II

• 发表时间: 2006
• 作者: O. Sate ;M. Kato
• 通讯作者: M. Kato

Electronic properties of nano-structured anisotropic superconductors

纳米结构各向异性超导体的电子特性

• 发表时间: 2008
• 期刊: J.Phys.Chem.Solids (印刷中)
• 作者: M.Kato;T.Koyama;M.Machida;M.Hayashi;H.Ebisawa;T.Ishida
• 通讯作者: T.Ishida

Artificial Spin System Using Composite Structures of d- and s-wave Superconductors

使用 d 波和 s 波超导体复合结构的人工自旋系统

• 发表时间: 2007
• 期刊: J.Magn.Magn.Mater 310
• 作者: M.Kato;M.Hirayama;S.Nakajima;T.Koyama;M.Machida;T.Ishida
• 通讯作者: T.Ishida