论文标题
螺旋rashba超导体中的磁激发
Magnetic excitations in the helical Rashba superconductor
论文作者
论文摘要
我们研究了具有反转对称性断裂和强烈的rashba旋转轨耦合的非中心超导体的螺旋状态下的磁激发光谱。为此，我们在存在强大的RASHBA分裂，超导间隙和外部场的情况下得出了动态自旋响应函数的一般表达，从而导致库珀对稳定在螺旋状态下具有有限的总体动量。后者的特征是具有不同的准颗粒分散体的配对和未配对状态的动量空间区域。磁反应由i）在配对和未配对区域内和之间的激发ii）异常相干因子以及iii）由于螺旋rashba旋转纹理而引起的其他自旋矩阵元素。我们表明，因此，典型的相关真实空间和自旋空间各向异性出现在动态敏感性中，在无弹性中子散射研究中，可以观察到是螺旋超导状态的特征指纹。
We investigate the magnetic excitation spectrum in the helical state of a noncentrosymmetric superconductor with inversion symmetry breaking and strong Rashba spin-orbit coupling. For this purpose, we derive the general expressions of the dynamical spin response functions under the presence of strong Rashba splitting of conduction bands, superconducting gap, and external field which lead to stabilization of Cooper pairs with finite overall momentum in a helical state. The latter is characterized by momentum space regions of paired and unpaired states with different quasiparticle dispersions. The magnetic response is determined by i) excitations within and between both paired and unpaired regions ii) anomalous coherence factors and iii) additional spin matrix elements due to helical Rashba spin texture of bands. We show that as a consequence typical correlated real space and spin space anisotropies appear in the dynamical susceptibility which would be observable as a characteristic fingerprint for a helical superconducting state in inelastic neutron scattering investigations.
