论文标题
Landau级别填充$ν= 1/7 $的2D电子的相关状态
Correlated states of 2D electrons near the Landau level filling $ν=1/7$
论文作者
论文摘要
在低兰道级填充因子（$ν\ lysSIM1/6 $）上，二维电子系统（2DES）的基态一直是凝结物问题的兴趣和争议的话题。在最近的超高动力GAAS 2DESS质量的突破之后，我们在实验中重新审视了这个问题，并研究了减少疾病的影响。在GAAS 2DES中，密度$ n = 6.1 \ times10^{10} $/cm $^2 $和移动性$μ= 25 \ 25 \ times10^6 $ cm $^2 $/vs，我们在纵向磁心固定率（$ r_ {xx} $）$ c $ c $ n $ n $ n $ n $ n $ n $ n $ n $ n $ n $ n $ s s $在$ r_ {xx} $ at $ν= 2/13 $中，也有一个明显的迹象表明，最低限度的最低限度。当$ν\ lysSIM1/6 $时，绝缘阶段仍然主要是主导，但这些最小值强烈表明，即使在非常低的Landau级别填充限制中，符合Jain序列$ν= P/（2MP \ pm1）$的填充因子的存在。从关系中得出的磁场依赖性激活能$ r_ {xx} \ propto e^{e_a/2kt} $证实了此视图，并暗示当$ν\ neq p/（2mp \ pm1）$时存在固定的wigner固态。在密度较低的另一个样品中也可以看到类似的结果，从而进一步推广了我们的观察结果。
The ground state of two-dimensional electron systems (2DESs) at low Landau level filling factors ($ν\lesssim1/6$) has long been a topic of interest and controversy in condensed matter. Following the recent breakthrough in the quality of ultra-high-mobility GaAs 2DESs, we revisit this problem experimentally and investigate the impact of reduced disorder. In a GaAs 2DES sample with density $n=6.1\times10^{10}$ /cm$^2$ and mobility $μ=25\times10^6$ cm$^2$/Vs, we find a deep minimum in the longitudinal magnetoresistance ($R_{xx}$) at $ν=1/7$ when $T\simeq104$ mK. There is also a clear sign of a developing minimum in the $R_{xx}$ at $ν=2/13$. While insulating phases are still predominant when $ν\lesssim1/6$, these minima strongly suggest the existence of fractional quantum Hall states at filling factors that comply with the Jain sequence $ν=p/(2mp\pm1)$ even in the very low Landau level filling limit. The magnetic field dependent activation energies deduced from the relation $R_{xx}\propto e^{E_A/2kT}$ corroborate this view, and imply the presence of pinned Wigner solid states when $ν\neq p/(2mp\pm1)$. Similar results are seen in another sample with a lower density, further generalizing our observations.
