Quarter-Filled Honeycomb Lattice with a Quantized Hall Conductance

磁场作用下一维四分之一填充带系统中电荷密度波和自旋密度波的共存态

Coexistent State of Charge Density Wave and Spin Density Wave in One-Dimensional Quarter Filled Band Systems under Magnetic Fields

从理论上研究了磁场如何增强一维四分之一填充带中电荷密度波和自旋密度波的共存状态。我们发现，当电子间的关联很强时，自旋密度波态在高磁场下被抑制，而电荷密度波态仍然存在。这将在X射线测量等实验中观察到。

Edge states in the three-quarter filled system, $α$-(BEDT-TTF)$_2$I$_3$

We study the edge states in the two-dimensional conductor $α$-(BEDT-TTF)$_2$I$_3$ theoretically. We show that the Dirac points and the edge states appear at the 3/4 and 1/4 filling as well as the half filling, due to four sites in the unit cell. This situation is in contract with the graphene, where the Dirac points and the edge states appear only at the half filling case. It is shown that the localization length of the edge states can become very large.

磁场作用下一维四分之一填充系统中的两种共存态

Two Kinds of the Coexistent States in One-Dimensional Quarter -Filled Systems under Magnetic Fields

研究了在磁场作用下，一维四分之一填充系统中库仑相互作用到达次近邻时自旋密度波（SDW）和电荷密度波（CDW）的共存状态。结果表明，在高磁场下，$2k_{\rm F}$-SDW和$2k_{\rm F}$-CDW共存时，电荷有序被抑制，$2k_{\rm F}$-SDW转变为具有不同自旋取向的$2k_{\rm F}$-SDW;而在$2k_{\rm F}$ -SDW和$4k_{\rm F}$共存时，$4k_{\rm F}$-CDW仍然存在，$2k_{\rm F}$ -SDW被抑制.当格位间库仑相互作用较强时，电荷序的临界温度高于自旋序的临界温度。这些将在实验中观察到，如X射线散射测量和NMR。

双层石墨烯中通过子态揭示的四分之一和二分之一填充量子霍尔态及其拓扑序

Quarter- and half-filled quantum Hall states and their topological orders revealed by daughter states in bilayer graphene

在超洁净双层石墨烯中观察到四分之一填充态及其Levin-Halperin子态，补全了半填充平台序列，揭示了非阿贝尔拓扑序的交替模式及复合费米子配对竞争。

Quarter-filled Kane-Mele Hubbard model: Dirac half-metals

Recent experimental success in the realization of two-dimensional (2D) magnetism has stimulated the search for new magnetic 2D materials with strong magnetic anisotropy and high Curie temperature. One promising subgroup of 2D magnetic systems are Dirac half-metals (DHM) which have gained a lot of interest recently, as they host a high-temperature quantum anomalous Hall effect (QAHE). This article discusses predictions for intrinsic DHMs and identifies them as realizations of the Kane-Mele Hubbard model at quarter filling. This proposed unification contributes to a firmer understanding of these…

Half-filled Kondo lattice on the honeycomb lattice

The unique linear density of state around the Dirac points for the honeycomb lattice brings much novel features in strongly correlated models. Here we study the ground-state phase diagram of the Kondo lattice model on the honeycomb lattice at half-filling by using an extended mean-field theory. By treating magnetic interaction and Kondo screening on an equal footing, it is found that besides a trivial discontinuous first-order quantum phase transition between well-defined Kondo insulator and antiferromagnetic insulating state, there can exist a wide coexistence region with both Kondo screening…