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arXiv 2408.00841cond-mat.str-el
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Shastry-Sutherland晶格上的交变磁性

Altermagnetism on the Shastry-Sutherland lattice

Francesco Ferrari, Roser Valenti

AI总结:

本文用变分蒙特卡罗方法研究Shastry-Sutherland晶格上Hubbard模型中的d波交变磁性,揭示其基态性质、金属-绝缘体转变、掺杂稳定性及Mott绝缘态中的自旋劈裂,并探讨其在有机电荷转移盐中的实现。

摘要:

受近期交变磁性(altermagnetism)研究进展的启发,我们研究了Shastry-Sutherland晶格上的Hubbard模型。在该模型中,电子之间的在位库仑排斥诱导了一种交错磁序的出现,其中相反的磁性子晶格仅通过旋转和滑移反射相互关联,而不通过反演或平移关联。因此,该磁相表现出交变磁特性,即在没有净磁化的情况下,电子激发存在有限的(非相对论性)Zeeman劈裂。通过基于Jastrow-Slater波函数的变分蒙特卡罗方法(该方法考虑了超越单粒子近似的电子关联效应),我们研究了d波交变磁性如何在系统基态性质和谱函数中体现。我们刻画了半填充时交变磁相之间的金属-绝缘体转变,以及交变磁性随掺杂变化的稳定性。单粒子谱函数的计算显示了电子激发的自旋劈裂本质,在Mott绝缘区域内同样如此。我们讨论了该模型在有机α-或κ-(BEDT-TTF)₂X电荷转移盐体系中可能的实现途径。

英文摘要:

Motivated by recent developments on altermagnetism, we investigate the Hubbard model on the Shastry-Sutherland lattice, where the onsite repulsion between electrons induces the onset of a staggered magnetic order in which opposite magnetic sublattices are related to each other only by rotations and glide reflections, and not by inversion nor translations. As a consequence, the magnetic phase displays an altermagnetic character, i.e. a finite (non-relativistic) Zeeman splitting of the electronic excitations, despite the absence of a net magnetization. By means of a variational Monte Carlo approach based on Jastrow-Slater wave functions, which accounts for electronic correlations beyond the single-particle approximation, we study how $d$-wave altermagnetism shows up in the ground state properties and in the spectral function of the system. We characterize the metal-insulator transition between altermagnetic phases at half-filling and the stability of altermagnetism as a function of doping. The calculation of the single-particle spectral function displays the spin-split nature of the electronic excitations, also within the Mott insulating regime. We discuss possible realizations of the model in the context of organic $α$- or $κ$-(BEDT-TTF)$_2$X charge transfer salts.

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