基于格点规范理论强耦合展开的单层石墨烯手征能隙和集体激发

强磁场下单层石墨烯的涌现费米子动力学对称性

Emergent Fermion Dynamical Symmetry for Monolayer Graphene in a Strong Magnetic Field

本研究综述强磁场下单层石墨烯的物理，以SO(8)费米子动力学对称性揭示其涌现自由度的支配规律，为强关联态研究提供新视角。

SiC表面单层和双层石墨烯非均匀电子结构的扫描隧道光谱研究

Scanning tunneling spectroscopy of inhomogeneous electronic structure in monolayer and bilayer graphene on SiC

我们提出了一个扫描隧道光谱（STS）的本地电子结构的SiC（0001）表面上外延生长的单层和双层石墨烯的研究。低电压的形貌图像揭示了精细的原子级碳网络，而较高的偏置图像主要是新兴的空间不均匀的大尺度结构，类似于SiC（0001）的富碳重建。STS光谱显示了单层和双层石墨烯/SiC在零偏压附近的~100 meV间隙样特征，以及间隙边缘上方电子结构的显著空间不均匀性。SiC/石墨烯界面处的纳米级结构被认为与所观察到的电子空间不均匀性相关。这些结果对于涉及石墨烯/SiC中的电子输运或隧穿的潜在器件是重要的。

Dirac Cone Metric and the Origin of the Spin Connections in Monolayer Graphene

We show that the modulation of the hopping amplitudes in the honeycomb lattice of the monolayer graphene uniquely defines a metric which corresponds to the shape of the Dirac cone. The spin connection of this effective metric field can be obtained from the microscopic tight-binding Hamiltonian exactly, completing the analogy between the sublattice pseudospin travelling in the monolayer graphene with ripples and strain fields, and the real spin $1/2$ fermion travelling in a curved space. The effective metric as seen by the sublattice pseudospin is different from the real space metric as defined…

Incompressible Even Denominator Fractional Quantum Hall States in the Zeroth Landau Level of Monolayer Graphene

Incompressible even denominator fractional quantum Hall states at fillings $ν= \pm \frac{1}{2}$ and $ν= \pm \frac{1}{4}$ have been recently observed in monolayer graphene. We use a Chern-Simons description of multi-component fractional quantum Hall states in graphene to investigate the properties of these states and suggest variational wavefunctions that may describe them. We find that the experimentally observed even denominator fractions and standard odd fractions (such as $ν=1/3, 2/5$, etc.) can be accommodated within the same flux attachment scheme and argue that they may arise from sublat…

The Ground State of Monolayer Graphene in a Strong Magnetic Field

Graphene SU(4) quantum Hall symmetry is extended to SO(8), permitting analytical solutions for graphene in a magnetic field that break SU(4) spontaneously. We recover standard graphene SU(4) physics as one limit, but find new phases and new properties that may be relevant for understanding the ground state. The graphene SO(8) symmetry is found to be isomorphic to one that occurs extensively in nuclear structure physics, and very similar to one that describes high-temperature superconductors, suggesting deep mathematical connections among these physically-different fermionic systems.

单层和双层石墨烯中费米速度的增强

Fermi Velocity Enhancement in Monolayer and Bilayer Graphene

在单层石墨烯片中，非局域带间交换导致重正化费米表面有效质量，其在低载流子密度极限下消失。我们报告的费米表面有效质量重整化的单层和AB堆叠的双层石墨烯的比较研究。我们解释了为什么在双层的情况下，质量不接近零，虽然它的值仍然强烈抑制。

Topological states in double monolayer graphene

Motivated by the experiments on double monolayer graphene that observe a variety of fractional quantum Hall states [Liu et al., Nat. Phys. 15, 893 (2019); Li et al., Nat. Phys. 15, 898 (2019)], we study the special setting in which two monolayers have different areas. It has not been considered before and allows us to construct a class of exotic topological states. The elementary excitations of these states do not carry fractional charges but obey fractional statistics. This is in sharp contrast to all previously studied cases, where the two properties are intimately connected and serve as hal…

Dirac Fermion Cloning, Moir$\bf{é}$ Flat Bands and Magic Lattice Constants in Epitaxial Monolayer Graphene

Tuning interactions between Dirac states in graphene has attracted enormous interest because it can modify the electronic spectrum of the two-dimensional material, enhance electron correlations, and give rise to novel condensed-matter phases such as superconductors, Mott insulators, Wigner crystals and quantum anomalous Hall insulators. Previous works predominantly focus on the flat band dispersion of coupled Dirac states from different graphene layers. In this work, we propose a new route to realizing flat band physics in monolayer graphene under a periodic modulation from substrates. We take…

单层石墨烯中分数量子霍尔态的集体激发

Collective excitations of fractional quantum Hall states in monolayer graphene

本文通过数值方法研究了单层石墨烯中分数量子霍尔态的集体激发，重点分析了允许手性对称性破缺序的态，并探讨了填充因子和磁通绑定方案对两类变分态激发谱的影响。

大尺度单层石墨烯中的本征太赫兹等离子体和磁等离子体

Intrinsic Terahertz Plasmons and Magnetoplasmons in Large Scale Monolayer Graphene

我们发现，在SiC上外延生长的石墨烯中，由于自然的纳米级不均匀性，如衬底梯田和皱纹，Drude吸收被转化为强的太赫兹等离子体峰。等离子体激元的激发极大地改变了磁光响应，特别是法拉第旋转。这使得石墨烯成为等离子体控制磁光现象的独特场所，这要归功于回旋质量比传统等离子体材料（如贵金属）小2个数量级。

超晶格Dirac点和空间相关费米速度在波纹石墨烯单分子膜中存在的证据

Evidence for Superlattice Dirac Points and Space-dependent Fermi Velocity in Corrugated Graphene Monolayer

最近的研究表明，周期势可以在石墨烯中产生能量为（是石墨烯的费米速度，G是倒易超晶格矢量）的超晶格狄拉克点。在这里，我们进行扫描隧道显微镜和光谱研究的波纹石墨烯单层铑箔。我们发现，纳米波长的准周期波纹的波纹石墨烯引起弱的一维（1D）电子势，从而导致超晶格狄拉克点的出现。超晶格的狄拉克点的位置是空间依赖的，并显示出广泛的分布值。我们证明了超晶格空间相关的狄拉克点与空间相关的费米速度密切相关，这可能是由于波纹石墨烯中的局域应变和强电子-电子相互作用的影响。