论文标题
原位控制障碍筛查对分数量子厅效应和复合特性传输的影响
Impact of in-situ controlled disorder screening on fractional quantum Hall effects and composite-fermion transport
论文作者
论文摘要
我们研究了由于远程杂质（RI）引起的随机潜力及其原位受控筛选对Landau级填充因子$ν= 1/2 $围绕分数量子厅效应（FQHES）的影响。通过使用双门GAAS量子井（QW），该实验可以实现，该量子允许对QW中的二维电子系统的密度$ n_ {e} $独立控制，并且该（$ n_ \ text {sl} $）在调制的超级线中的多余电子中（$ n_ \ text {sl} $）。由于在固定的$ n_ {e} $下减少$ n_ \ text {sl} $来减少筛选，我们观察到减少了从热激活中引发的FQHES明显能量差距，这表明宽阔的$γ$ Composite Fermions（CFS）的疾病销量相应增加。有趣的是，$γ$的增加伴随着纵向电阻率在$ν= 1/2 $（$ρ_{1/2} $）下的明显增加，与$γ$的相关性比电子流动性$ $ $ $更强。对RI筛选的原位控制使我们能够将RIS和背景杂质（BIS）对$ρ_{1/2} $的贡献取消，后者与CF理论非常一致。我们构建了一个缩放图，有助于估计给定$ n_ {e} $和$μ$的$ρ_{1/2} $的BI贡献。
We examine the impact of random potential due to remote impurites (RIs) and its in-situ controlled screening on fractional quantum Hall effects (FQHEs) around Landau-level filling factor $ν= 1/2$. The experiment is made possible by using a dual-gate GaAs quantum well (QW) that allows for the independent control of the density $n_{e}$ of the two-dimensional electron system in the QW and that ($n_\text{SL}$) of excess electrons in the modulation-doping superlattice. As the screening is reduced by decreasing $n_\text{SL}$ at a fixed $n_{e}$, we observe a decrease in the apparent energy gap of the FQHEs deduced from thermal activation, which signifies a corresponding increase in the disorder broadening $Γ$ of composite fermions (CFs). Interestingly, the increase in $Γ$ is accompanied by a noticeable increase in the longitudinal resistivity at $ν= 1/2$ ($ρ_{1/2}$), with a much stronger correlation with $Γ$ than electron mobility $μ$ has. The in-situ control of RI screening enables us to disentangle the contributions of RIs and background impurities (BIs) to $ρ_{1/2}$, with the latter in good agreement with the CF theory. We construct a scaling plot that helps in estimating the BI contribution to $ρ_{1/2}$ for a given set of $n_{e}$ and $μ$.
