arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1609.01703cond-mat.str-elcond-mat.mes-hall
收藏

分数量子霍尔效应中磁振子极小值的位置

Positions of the magnetoroton minima in the fractional quantum Hall effect

Ajit C. Balram, Songyang Pu

摘要:

分数量子霍尔态的大量激发在微观上被非常准确地理解为复合费米子在其类朗道$Λ$能级上的激发。特别是,复合费米子激子的色散,这是最低的能量自旋守恒中性激发,显示填充因子特定的最小值称为“磁子”最小值。Simon和Halperin采用复合费米子的Chern-Simons场论[Phys. Rev. B { \bf 48},17368(1993)]来预测磁子极小值的位置。最近,Golkar \emph{et al.} [Phys. Rev. Lett. { \bf 117},216403(2016)]已经将中性激发建模为复合费米子费米海的变形,这导致对磁子最小值的位置的预测。利用微观复合费米子理论的方法,我们计算了填充因子为5/11时沿序列$s/(2s+1)$的旋子极小值的位置,发现它们与陈-西蒙斯复合费米子场论和Golkar \emph{et al.}的理论都相当吻合。我们还发现,与Golkar \emph{et al.}的理论一致,旋子极小值的位置对微观相互作用不敏感。作为我们计算的副产品,我们得到了电荷和中性隙的完全自旋极化状态沿序列$s/(2s\pm 1)$在最低的朗道水平和$n=1$朗道水平的石墨烯。

英文摘要:

The multitude of excitations of the fractional quantum Hall state are very accurately understood, microscopically, as excitations of composite fermions across their Landau-like $Λ$ levels. In particular, the dispersion of the composite fermion exciton, which is the lowest energy spin conserving neutral excitation, displays filling-factor-specific minima called "magnetoroton" minima. Simon and Halperin employed the Chern-Simons field theory of composite fermions [Phys. Rev. B {\bf 48}, 17368 (1993)] to predict the magnetoroton minima positions. Recently, Golkar \emph{et al.} [Phys. Rev. Lett. {\bf 117}, 216403 (2016)] have modeled the neutral excitations as deformations of the composite fermion Fermi sea, which results in a prediction for the positions of the magnetoroton minima. Using methods of the microscopic composite fermion theory we calculate the positions of the roton minima for filling factors up to 5/11 along the sequence $s/(2s+1)$ and find them to be in reasonably good agreement with both the Chern-Simons field theory of composite fermions and Golkar \emph{et al.}'s theory. We also find that the positions of the roton minima are insensitive to the microscopic interaction in agreement with Golkar \emph{et al.}'s theory. As a byproduct of our calculations, we obtain the charge and neutral gaps for the fully spin polarized states along the sequence $s/(2s\pm 1)$ in the lowest Landau level and the $n=1$ Landau level of graphene.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑