Fe4 cluster as the smallest 3D Fe cluster with unique quantum magnetic levitation effect on graphene

• Published in: Applied surface science 2023-08, Vol.628, p.157315, Article 157315
• Main Authors: Ma, Ning-Gui, Zhang, Yong-Jia, Zhang, He-Na, Mu, Hui-Min, Zhang, Yong, Wang, Xiao-Chun
• Format: Article
• Language: English
• Subjects: Extremely-high density independent quantum dots; First-principles calculations; Spontaneous quantum magnetic levitation; Two-dimensional diamagnetism
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2023.157315

[Display omitted] •The Fe4 cluster is magnetically levitated on graphene.•The low diffusion energy barrier leads to the low energy consumption.•Fe4 clusters have multiple quantum states on graphene.•The repulsion force results in isolated quantum dots with ultrahigh density. The unique quantum magnetic levitation effect of small metallic clusters adsorbed on graphene has been studied for their minimal energy configurations in this work. Using first-principles calculations, we specially focus on the tetrahedral Fe4 clusters in a corn-like configuration for the induced magnetic moments in the Fe4 cluster and graphene. Firstly, the 3D magnetic Fe4 cluster spontaneously induced a diamagnetic moment in graphene in the absence of external energy injection. Additionally, as the smallest 3D particle (among Fen clusters), the Fe4 cluster can be levitated by the repulsive magnetic interaction between the Fe cluster and graphene. The maximum energy barrier between different adsorption configurations of the Fe4 cluster on graphene is as low as 0.8 eV, making the Fe4 cluster diffusible between sites with a minimal external force. The conversion energy barrier is relatively low, resulting in low energy consumption. Importantly, the repulsion between Fe clusters may lead to the formation of an ultrahigh-density (1.18 × 1014/cm2) isolated quantum dot array and avoids the formation of larger clusters. These quantum states might be usable for nanoscale data storage devices for next-generation computing applications, and the small diffusion barrier might offer potential applications in quantum mechanical sensing and nanoscale magnetic levitation.