Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
Center for Quantum Science and Engineering, National Taiwan University, Taipei 10617, Taiwan.
Sci Rep. 2016 Jul 26;6:29919. doi: 10.1038/srep29919.
We investigate the effect of the Rashba interaction on two dimensional superconductivity. The presence of the Rashba interaction lifts the spin degeneracy and gives rise to the spectrum of two bands. There are intraband and interband pairs scattering which result in the coupled gap equations. We find that there are isotropic and anisotropic components in the gap function. The latter has the form of cos φk where . The former is suppressed because the intraband and the interband scatterings nearly cancel each other. Hence, -the system should exhibit the p-wave superconductivity. We perform a detailed study of electron-phonon interaction for 2DEG and find that, if only normal processes are considered, the effective coupling strength constant of this new superconductivity is about one-half of the s-wave case in the ordinary 2DEG because of the angular average of the additional in the anisotropic gap function. By taking into account of Umklapp processes, we find they are the major contribution in the electron-phonon coupling in superconductivity and enhance the transition temperature Tc.
我们研究了 Rashba 相互作用对二维超导性的影响。 Rashba 相互作用的存在消除了自旋简并,并导致了两个能带的能带结构。存在着带内和带间对散射,这导致了耦合能隙方程。我们发现,在能隙函数中有各向同性和各向异性分量。后者的形式为 cos φk,其中φ是动量空间中波矢 k 的角度。前者被抑制,因为带内和带间散射几乎相互抵消。因此,系统应该表现出 p 波超导性。我们对 2DEG 中的电子-声子相互作用进行了详细研究,发现如果只考虑正常过程,由于各向异性能隙函数中附加项的角度平均,这种新超导性的有效耦合强度常数约为普通 2DEG 中 s 波情况的一半。通过考虑到 Umklapp 过程,我们发现它们是超导中电子-声子耦合的主要贡献,并提高了转变温度 Tc。