当前位置: X-MOL 学术Jetp 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.)
Phase Separation in a Spin Density Wave State of Twisted Bilayer Graphene
JETP Letters ( IF 1.3 ) Pub Date : 2021-02-01 , DOI: 10.1134/s0021364020220130
A. O. Sboychakov , A. V. Rozhkov , K. I. Kugel , A. L. Rakhmanov

Twisted bilayer graphene at the so-called magic twist angle θ ∼ 1° is theoretically studied. In the absence of interaction between electrons, the system under study is characterized by four almost degenerate flat bands near the Fermi level. The electron-electron interaction lifts this degeneracy and stabilizes a certain order parameter in the system. We assume that the arising order parameter corresponds to a spin density wave. The evolution of such spin density wave state upon doping is analyzed. It is shown that, in the doping range where this order parameter exists, the homogeneous state of the system can be unstable to phase separation. Namely, the doping dependence of the chemical potential is nonmonotonic, which is consistent with recent experiments. Phases in the inhomogeneous state are characterized by an even number (ν = 0, ±2, ±4) of electrons per supercell. This allows explaining some features in the behavior of the conductivity of the doped system.



中文翻译:

扭曲双层石墨烯自旋密度波态的相分离

理论上研究了所谓的魔术扭曲角θ〜1°的双层石墨烯的扭曲。在电子之间没有相互作用的情况下,所研究的系统的特征是在费米能级附近有四个几乎简并的平坦带。电子-电子相互作用消除了这种简并并稳定了系统中的某个有序参数。我们假设上升阶参数对应于自旋密度波。分析了这种自旋密度波状态在掺杂时的演变。结果表明,在存在该有序参数的掺杂范围内,系统的均匀状态对于相分离可能不稳定。即,化学势的掺杂依赖性是非单调的,这与最近的实验一致。非均相状态的特征是偶数(ν= 0,±2,每个超级电池有±4个电子。这允许解释掺杂系统的电导率行为中的一些特征。

更新日期:2021-02-02
down
wechat
bug