Quantum phenomena in unconventional superconductor junctions

非常规超导结中的量子现象

• 批准号: 17340106
• 负责人: TANAKA Yukiko
• 金额: $ 7.36万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17340106/
• 关键词: Proximity effect; Helium 3; Sr2RuO4; Symmetry of the Cooper pair; Odd frequency paring; スピン3重項超伝導; 超流動; トンネル効果; メゾスコピック効果

Symmetry of the Cooper pair can be generally classified into even-frequency spin-singlet even-parity (ESE) state, even-frequency spin-triplet odd-parity (ETO) state, odd-frequency spin-triplet even-parity (OTE) state and odd-frequency spin-singlet odd-parity (OSO) state. We present a general theory of the proximity effect in junctions between diffusive normal metals (DN) and unconventional superconductors in the framework of the Green's function formalism. Above four possible symmetry classes in a superconductor are considered: ESE, ETO, OTE and OSO state. For each of the above four cases symmetry and spectral properties of the induced pair amplitude in the DN are determined where only the even-parity s-wave pairing is possible due to the impurity scattering in DN. It is shown that the pair amplitude in a DN belongs respectively to an ESE, OTE, OTE and ESE pairing state In the presence of the Odd-frequency pairing state, the resulting density of state has a zero energy peak. The genera … More tion of the OTE state in the DN attached to the ETO p-wave superconductor is of particular interest in the relevance to the novel proximity effect in Sr2RuO4 junctions. In order to resolve this point, we are now preparing the junction made from Sr2RuO4 Using FIG technique. We further demonstrate that, quite generally, the spin-singlet even-parity (spin-triplet odd-parity) pair potential in a superconductor induces the odd-frequency pairing component with spin-singlet odd-parity (spin-triplet even-parity) near interfaces. The magnitude of the induced odd-frequency component is enhanced in the presence of the midgap Andreev resonant state due to the sign change of the anisotropic pair potential at the interface. We discussed the electronic Raman spectra of the quasi-two-dimensional spin-triplet superconductor Sr2RuO4. The Raman spectra are calculated using the Keldysh Green's function theory taking into account the order parameter collective mode. We take into account the effect of impurity scattering. The impurity scattering gives rise to considerable modification of the contribution from the quasiparticle excitations to the Raman spectra and simultaneously to the broadening of the collectivemode resonance peak and the shift of the peak position. Less

库珀对的对称性通常可以分为偶频自旋单重态偶宇称（ESE）态、偶频自旋三重态奇宇称（ETO）态、奇频自旋三重态偶宇称（OTE）态和奇频自旋单重态奇宇称（OSO）态。本文在绿色函数理论的框架下，提出了扩散正常金属（DN）与非常规超导体结中邻近效应的一般理论。考虑了超导体中四种可能的对称性：ESE、ETO、OTE和OSO态。对于上述四种情况的对称性和光谱特性的诱导对振幅的DN中确定的偶宇称s波配对是可能的，由于在DN中的杂质散射。结果表明，DN中的电子对振幅分别属于ESE、OTE、OTE和ESE对态。在奇频对态存在时，所得到的态密度有一个零能量峰。属 ...更多信息 在连接到ETO p波超导体的DN中的OTE状态的作用与Sr2RuO4结中的新颖邻近效应的相关性特别令人感兴趣。为了解决这一点，我们现在正在使用FIG技术制备由Sr2RuO4制成的结。我们进一步证明，相当普遍的，自旋单重态偶宇称（自旋三重态奇宇称）对势在超导体中诱导的奇频率配对组件与自旋单重态奇宇称（自旋三重态偶宇称）界面附近。由于界面处各向异性对势的符号变化，在存在中间带隙Andreev共振态的情况下，诱导的奇频分量的幅度增强。本文讨论了准二维自旋三重态超导体Sr_2RuO_4的电子拉曼光谱。拉曼光谱计算使用Keldysh绿色函数理论考虑到有序参数集体模式。我们考虑了杂质散射的影响。杂质散射引起准粒子激发对拉曼谱贡献的显著改变，同时引起集体模共振峰的展宽和峰位的移动。少

项目成果

Resonant peak in the density of states in normal-metal/diffusive ferromagnet / superconductor junction

普通金属/扩散铁磁体/超导体结中态密度的共振峰

• 发表时间: 2005
• 期刊: Physical Review B 72
• 作者: Y.Tanaka;Y.Tanaka;Y.Asano;T.Yokoyama;M.Miura;Y.Tanaka;Y.Tanaka;M.Miura;T.Yokoyama;M.Miura;M.Miura;M.Miura;M.Miura;Y.Tanaka;Y.Asano;S.Kawabata;T.Yokoyama
• 通讯作者: T.Yokoyama

Theory of enhanced proximity effect by midgap Andreev resonant state in diffusive normal-metal/triplet superconductor junctions

• DOI: 10.1103/physrevb.71.094513
• 发表时间: 2004-11
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Yukio Tanaka;S. Kashiwaya;T. Yokoyama

Manifestation of the odd-frequency spin-triplet pairing stat in diffusive ferromagnet / superconductor junctions

扩散铁磁体/超导体结中奇频自旋三重态配对状态的表现

• 期刊: Physical Review B Vol.75
• 作者: Y.Tanaka;Y.Tanaka;Y.Asano;T.Yokoyama;M.Miura;Y.Tanaka;Y.Tanaka;M.Miura;T.Yokoyama;M.Miura;M.Miura;M.Miura;M.Miura;Y.Tanaka;Y.Asano;S.Kawabata;T.Yokoyama;Y.Tanaka;T.Yokoyama;Y.Asano;T.Yokoyama
• 通讯作者: T.Yokoyama

Effect of Order Parameter Collective Mode on Electronic Raman Spectra of Spin-triplet superconductor Sr_2RuO_4

序参数集合模式对自旋三重态超导体Sr_2RuO_4电子拉曼光谱的影响

• 发表时间: 2007
• 期刊: J. Phys. Soc. Jpn. 76
• 作者: M. Tsukada;K. Tagami and N. Watanabe;M. Miura
• 通讯作者: M. Miura

Effect of Order Parameter Collective Mode on Electronic Raman Spectra of Spin-triplet superconductor Sr2Ru04

有序参数集合模式对自旋三重态超导体Sr2Ru04电子拉曼光谱的影响

• 发表时间: 2007
• 期刊: Journal of the Physical Society of Japan 76
• 作者: Y.Tanaka;Y.Tanaka;Y.Asano;T.Yokoyama;M.Miura;Y.Tanaka;Y.Tanaka;M.Miura;T.Yokoyama;M.Miura
• 通讯作者: M.Miura