石墨烯环内、外缘态的数值研究

Forming Weakly Interacting Multi Layers of Graphene by using Atomic Force Microscope Tip Scanning and Evidence of Competition Between Inner and Outer Raman Scattering Processes Piloted by Structural Defects

We report on an alternative route based on nanomechanical folding induced by AFM tip to obtain weakly interacting multi-layer graphene (wi-MLG) from a chemical vapor deposition (CVD) grown single-layer graphene (SLG). The tip first cuts, then pushes and folds graphene during zigzag movements. The pushed graphene has been analyzed using various Raman microscopy plots: $A_D /A_G \times E_L{}^4$ vs $Γ_G$, $ω_{2D}$ vs $Γ_{2D}$, $Γ_{2D}$ vs $Γ_G$, $ω_{2D+/-}$ vs $Γ_{2D+/-}$, and $A_{2D-}/A_{2D+}$ vs $A_{2D}/A_G$. We show that the SLG in plane properties are maintained under the folding process and …

双层石墨烯内双共振拉曼散射过程的研究

On the inner Double-Resonance Raman scattering process in bilayer graphene

通过改变激发激光的能量，可以从双共振拉曼光谱中获得石墨烯系统的声子色散和电子结构。在先前的石墨烯共振拉曼研究中，电子结构在Slonczewski-Weiss-McClure（SWM）模型的框架中进行了分析，考虑了外部DR过程。在这项工作中，我们分析的数据考虑内部DR过程，并获得SWM参数，更好地与其他实验技术获得的。这一结果可能表明，石墨烯系统中的双共振过程仍然存在一个基本的悬而未决的问题。

Gapless states and current control in strongly distorted gated trilayer graphene

We investigate gated trilayer graphene partially devoid of outer layers and forming a system of two trilayers connected by a single layer of graphene. A difference in the stacking order of trilayers leads to the appearance of gapless states, one of which is mainly localized in the single graphene layer. We demonstrate that by changing the value of the gate voltage applied to the outer layers one can change the slope of E(k) of this state. As a consequence the direction of current flowing in the single layer graphene can also be changed, the effect that could be useful in practical applications…

六角石墨烯结构中的反铁磁性：环与点

Antiferromagnetism in hexagonal graphene structures: Rings vs dots

利用平均场哈伯德模型研究了具有锯齿形内边缘的六角石墨烯环中反铁磁相的形成。环的外边缘被认为是锯齿形或扶手椅形，我们发现，这两种类型的结构可以有一个更大的反铁磁相互作用相比，六边形点。这种差异可以部分归因于环中每单位面积的锯齿形边缘的数量比点中的多。此外，发现位于内环边缘上的边缘状态与点的边缘状态不同地杂交，这导致石墨烯环和点的磁性的重要差异。当外边缘具有锯齿形形状时，发现最大交错磁化。然而，窄环扶手椅外边缘被发现有较大的交错磁化比锯齿形六边形。边缘缺陷被示出具有最小的磁化效果时，外环边缘是扶手椅形。

Electronic properties of bilayer graphene with magnetic quantum structures studied using the Dirac equation

The electronic properties of bilayer graphene with a magnetic quantum dot and a magnetic quantum ring are investigated. The eigenenergies and wavefunctions of quasiparticle states are calculated analytically by solving decoupled fourth-order differential equations. For the magnetic quantum dot, in the case of a negative inner magnetic field, two peculiar characteristics of the eigenenergy evolution are found: (i) the energy eigenstates change in a stepwise manner owing to energy anticrossing and (ii) the quantum states approach zero energy. For the magnetic quantum ring, there is an angular mo…

石墨烯中重原子与外壳层$p$轨道电子的自旋轨道耦合

Spin Orbit Coupling in Graphene Induced by Heavy Adatoms with Electrons in the Outer-Shell $p$ Orbitals

石墨烯中提出的许多奇异性质依赖于增加自旋轨道耦合（SOC）的可能性。结合解析和数值紧束缚计算，我们研究了活性电子位于$p$轨道的重吸附原子诱导的SOC。根据吸附原子在石墨烯上的位置，出现不同类型的SOC。吸附原子处于空心位置时产生自旋守恒的本征SOC，而随机分布时产生自旋翻转的Rashba SOC，SOC与吸附原子浓度成线性关系，表明不同吸附原子之间不存在干涉效应.通过计算霍尔电导率，我们证明了吸附原子产生的拓扑量子霍尔相对非均匀自旋轨道耦合的稳定性。对于Pb吸附原子的情况下，我们发现，0.1吸附原子的浓度，每个碳原子产生的SOC的数量级为$\sim$ 40 $meV$。