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arXiv 1506.04809cond-mat.str-el
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一维自旋费米子模型中磁序、配对和相分离的相互作用

Interplay of Magnetic Order, Pairing and Phase Separation in a One Dimensional Spin Fermion Model

Wenjian Hu, Richard T. Scalettar, Rajiv R. P. Singh

摘要:

我们考虑一个晶格模型的巡回电子耦合到一个阵列的本地化的经典海森堡自旋。基态有序磁相的性质,从间接的自旋-自旋耦合介导的电子被确定为密度和自旋-费米子耦合$J$的函数。在一个固定的化学势下,螺旋相只存在于$J$的值以下,该值大约小于电子带宽的一半。当电子密度固定且接近半填充时,系统相分离为半填充反铁磁相和螺旋相。铁磁相被示出为完全极化,而螺旋相具有相等的上下自旋的混合。相分离在弱配对场$Δ$的存在下存在,但当$Δ$超过临界值$Δ_c$时消失。如果配对场足够大,则在强耦合$J$处会产生额外的螺旋态。这项研究的相关性,特别是相分离,相邻的巡回电子和本地化自旋的人工工程系统进行了讨论。特别是,我们提出了一种方法,它可能允许编织的马约拉纳费米子通过改变密度和移动它们的位置,因为它们被拉沿相分离边界。

英文摘要:

We consider a lattice model of itinerant electrons coupled to an array of localized classical Heisenberg spins. The nature of the ground state ordered magnetic phases that result from the indirect spin-spin coupling mediated by the electrons is determined as a function of density and the spin-fermion coupling $J$. At a fixed chemical potential, spiral phases exist only up to values of $J$ which are less than roughly half the electronic bandwidth. At a fixed electron density and near half filling, the system phase separates into a half-filled antiferromagnetic phase and a spiral phase. The ferromagnetic phases are shown to be fully polarized, while the spiral phases have equal admixture of up and down spins. Phase separation survives in the presence of weak pairing field $Δ$ but disappears when $Δ$ exceeds a critical value $Δ_c$. If pairing fields are large enough, an additional spiral state arises at strong coupling $J$. The relevance of this study, especially the phase separation, to artificially engineered systems of adjacent itinerant electrons and localized spins is discussed. In particular, we propose a method which might allow for the braiding of Majorana fermions by changing the density and moving their location as they are pulled along by a phase separation boundary.

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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