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arXiv 2007.05350cond-mat.mes-hallcond-mat.supr-con
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一维Andreev晶体中的能隙反转

Gap inversion in one-dimensional Andreev crystals

M. Rouco, F. S. Bergeret, I. V. Tokatly

摘要:

本文研究了一维超导导线中磁区的周期性排列。由于本地交换场,每个区域支持Andreev束缚态,这些束缚态在我们称为Andreev晶体(AC)的子带谱中杂交形成布洛赫带。作为一个例子,AC与铁磁和反铁磁的磁性区域的对齐被认为是。我们涉及的光谱不对称指数的自旋分辨哈密顿的自旋极化,并确定它作为可观察到的量化的激发间隙的关闭和重新打开。特别地,反铁磁AC表现出由无隙狄拉克相边界分离的带隙相序列。反铁磁AC在相邻的阶段之间的异质结支持在界面处的自旋极化的束缚态。在一个密切的类比狄拉克系统中的电荷分馏与质量反转,我们发现一个分馏的界面自旋。

英文摘要:

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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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