标题： 二维近铁磁全金属和铁磁半金属中的通过顺磁子和磁振子交换的超导性 显示英文标题

标题： Superconductivity via paramagnon and magnon exchange in a 2D near-ferromagnetic full metal and ferromagnetic half-metal

摘要： 我们研究二维电子系统中顺磁和铁磁有序相中的超导性，该系统具有抛物线费米子色散和短程排斥相互作用。 在顺磁相中，我们发现参数子传播子的弱动量依赖性会参数化地降低配对的起始温度，相较于假设参数子强色散的表观理论，并且改变了能隙函数的拓扑结构。 在铁磁相中，我们表明秩序立即极化了低能费米激发。 我们推导了由两个横向戈德斯通模介导的低能费米子之间的完全重整化配对相互作用，并表明它在空间奇数通道中是吸引的。 发现铁磁相中的配对温度是费米能的一小部分，远大于在转变附近的顺磁相中的温度。 我们的结果对于理解多谷石墨烯系统中接近巡游铁磁性的超导性具有相关性，特别是那些具有完整谷和自旋极化的系统。 显示英文摘要

摘要： We study superconductivity in paramagnetic and ferromagnetically-ordered phases in a two-dimensional electron system with parabolic fermionic dispersion and short-range repulsive interaction. In the paramagnetic phase, we find that a weak momentum dependence of a paramagnon propagator parametrically reduces the onset temperature for the pairing compared to that in phenomenological theories which assume a strong dispersion of a paramagnon and also changes the topology of the gap function. In the ferromagnetic phase, we show that the order instantly polarizes low-energy fermionic excitations. We derive the fully renormalized pairing interaction between low-energy fermions, mediated by two transverse Goldstone modes and show that it is attractive in a spatially-odd channel. The pairing temperature in the ferromagnetic phase is found to be a fraction of the Fermi energy, significantly larger than in the paramagnetic phase near the transition. Our results are relevant for understanding superconductivity in proximity to itinerant ferromagnetism in multi-valley graphene systems, particularly the ones with full valley and spin polarization.