论文标题
一维Andreev晶体中的间隙反转
Gap inversion in one-dimensional Andreev crystals
论文作者
论文摘要
我们研究一维超导线中磁区域的定期布置。由于局部交换场，每个区域都支持Andreev Bound指出，在我们所谓的Andreev Crystal（AC）的子仪谱中杂交形成Bloch频段。作为例证，考虑了具有铁磁和抗铁磁区域的ACS的AC。我们将自旋分辨的哈密顿量的光谱不对称指数与自旋极化相关联，并将其确定为可观察到的可观察到的量子，以量化激发差距的闭合和重新打开。特别是，抗铁磁ACS表现出一系列被无间隙狄拉克相边界隔开的间隙相。相邻相的抗铁磁AC在界面上的自旋偏振结合态之间的异缘界面。与质量反转的狄拉克系统中的电荷分数相似，我们发现界面旋转的分数化。
We study a periodic arrangement of magnetic regions in a one-dimensional superconducting wire. Due to the local exchange field, each region supports Andreev bound states that hybridize forming Bloch bands in the subgap spectrum of what we call the Andreev crystal (AC). As an illustration, ACs with ferromagnetic and antiferromagnetic alignment of the magnetic regions are considered. We relate the spectral asymmetry index of a spin-resolved Hamiltonian to the spin polarization and identify it as the observable that quantifies the closing and reopening of the excitation gap. In particular, antiferromagnetic ACs exhibit a sequence of gapped phases separated by gapless Dirac phase boundaries. Heterojunctions between antiferromagnetic ACs in neighboring phases support spin-polarized bound states at the interface. In a close analogy to the charge fractionalization in Dirac systems with a mass inversion, we find a fractionalization of the interface spin.
