Emergence of Ferromagnetism Due to Spontaneous Symmetry Breaking in a Twisted Bilayer Graphene Nanoflex,Nano Letters

当前位置： X-MOL 学术 › Nano Lett. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Emergence of Ferromagnetism Due to Spontaneous Symmetry Breaking in a Twisted Bilayer Graphene Nanoflex
Nano Letters ( IF 9.6 ) Pub Date : 2021-09-09 , DOI: 10.1021/acs.nanolett.1c01972
Dharmendra Pant , Sandip Aryal , Subhasish Mandal ₁ , Ranjit Pati

Affiliation

Twisted bilayer graphene exhibits many intriguing behaviors ranging from superconductivity to the anomalous Hall effect to ferromagnetism at a magic angle of ∼1°. Here, using a first-principles approach, we reveal ferromagnetism in a twisted bilayer graphene nanoflex. Our results demonstrate that when the energy gap of a twisted nanoflex approaches zero, electronic instability occurs and a ferromagnetic gap state emerges spontaneously to lower the energy. Unlike the observed ferromagnetism at a magic angle in the graphene bilayer, we notice the ferromagnetic phase appearing aperiodically between 0 and 30° in the twisted nanoflex. The origin of electronic instability at various twist angles is ascribed to the several higher-symmetry phases that are broken to lower the energy resulting from an aperiodic modulation of the interlayer interaction in the nanoflex. Besides unraveling a spin-pairing mechanism for the reappearance of the nonmagnetic phase, we have found orbitals at the boundary of nanoflex contributing to ferromagnetism.

中文翻译：

由于扭曲双层石墨烯 Nanoflex 中的自发对称性破坏导致铁磁性的出现

扭曲的双层石墨烯表现出许多有趣的行为，从超导性到异常霍尔效应，再到魔角约为 1° 的铁磁性。在这里，我们使用第一性原理方法揭示了扭曲双层石墨烯纳米柔性中的铁磁性。我们的结果表明，当扭曲的纳米柔性材料的能隙接近零时，会发生电子不稳定性，并且铁磁隙状态自发出现以降低能量。与在石墨烯双层中以魔角观察到的铁磁性不同，我们注意到铁磁相在扭曲的 nanoflex 中在 0 到 30° 之间不定期出现。不同扭曲角下电子不稳定性的起源归因于几个更高对称性的相位，这些相位被破坏以降低纳米柔性层间相互作用的非周期性调制所产生的能量。除了解开非磁性相重新出现的自旋配对机制外，我们还发现了纳米柔性边界处的轨道有助于铁磁性。

更新日期：2021-09-22

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11