磁自旋轨道石墨烯：Chern拓扑与光致霍尔响应
Magneto-spin-orbit graphene: Chern topology and photoinduced Hall response
- Saint Petersburg State University（圣彼得堡国立大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过第一性原理和有效模型计算，发现摩尔尺度堆叠决定磁自旋轨道石墨烯异质结构的Chern拓扑相，而埋藏界面缺陷可调节光致霍尔响应而不改变拓扑。
AI中文摘要：
磁自旋轨道石墨烯由于邻近效应可以承载Chern相，但在实际异质结构中，这些相依赖于衬底化学、局部堆叠配准，并可能因埋藏界面重构而改变。研究这些效应需要特别努力以考虑这些异质结构中经常出现的的长程摩尔条纹。我们通过第一性原理计算和有效的四带模型，针对四种面外磁化的Gr/(Au, Pt)/(Co, Mn)异质结构，在相称(2×2)和摩尔(9×9)超胞中研究了这一问题，其中后者包含Co基界面的失配位错。相称胞高估了电荷转移并夸大了谷不对称性，而摩尔平均则强烈减小了这两种效应，同时保持了可观的的自旋劈裂。Pt间隔层比Au介导更强的邻近效应，而用Mn替代Co则显著改变了有效交换相互作用的平衡，且这种改变依赖于间隔层。将失配位错引入Co基结构具有选择性，并调节了Gr/Au/Co中的狄拉克能隙或Gr/Pt/Co中的自旋劈裂。Gr/Pt/Co中的石墨烯在所有研究的超胞中表现出有效的铁磁Chern相，C=2。相比之下，其他三种成分的摩尔模型是亚铁磁且拓扑平凡的，C=0。然而，它们表现出螺旋度依赖的光致霍尔响应，在Gr/Au/Co中因失配位错重构而强烈增强。这项工作表明，摩尔尺度的堆叠控制了有效的Chern相和霍尔电导率，而埋藏界面缺陷在不改变拓扑的情况下调节了光致霍尔响应。
英文摘要：
Magneto-spin-orbit graphene can host Chern phases due to proximity interactions, but in realistic heterostructures these depend on substrate chemistry, local stacking registry and may be altered by buried-interface reconstruction. Investigation of these effects requires special efforts to take into account the long-range moire patterns that often arise for these heterostructures. We address this question using first-principles calculations and effective four-band models for four out-of-plane magnetized Gr/(Au, Pt)/(Co, Mn) heterostructures in commensurate (2 x 2) and moire (9 x 9) supercells where the latter include misfit dislocations for the Co-based interfaces. The commensurate cells overestimate charge transfer and exaggerate valley asymmetry, whereas moire averaging strongly reduces both effects while preserving sizable spin splittings. The Pt spacer mediates stronger proximity interactions than Au, while replacing Co by Mn substantially changes the balance of the effective exchange interactions in a spacer-dependent manner. Introduction of misfit dislocations into the Co-based structures is selective and tunes the Dirac gap in Gr/Au/Co or spin splittings in Gr/Pt/Co. Graphene in Gr/Pt/Co exhibits effective ferromagnetic Chern phase with C = 2 in all studied supercells. By contrast, the moire models of the other three compositions are ferrimagnetic and topologically trivial, with C = 0. Nevertheless, they exhibit helicity-dependent photoinduced Hall responses, which are strongly enhanced by misfit-dislocation reconstruction in Gr/Au/Co. This work demonstrates that moire-scale stacking controls the effective Chern phase and Hall conductivity, whereas buried-interface defects tune the photoinduced Hall response without changing the topology.
