Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA.
Phys Rev Lett. 2011 Dec 23;107(26):266802. doi: 10.1103/PhysRevLett.107.266802. Epub 2011 Dec 20.
We report the evolution of the fractional quantum Hall state (FQHS) at a total Landau level (LL) filling factor of ν=7/2 in wide GaAs quantum wells in which electrons occupy two electric subbands. The data reveal subtle and distinct evolutions as a function of density, magnetic field tilt angle, or symmetry of the charge distribution. At intermediate tilt angles, for example, we observe a strengthening of the ν=7/2 FQHS. Moreover, in a well with asymmetric change distribution, there is a developing FQHS when the LL filling factor of the symmetric subband ν(S) equals 5/2 while the antisymmetric subband has a filling factor of 1<ν(A)<2.
我们报告了在总 Landau 能级（LL）填充因子为 ν=7/2 的宽 GaAs 量子阱中电子占据两个电子子带的分数量子霍尔态（FQHS）的演化。这些数据揭示了作为密度、磁场倾斜角或电荷分布对称性的函数的微妙而明显的演化。例如，在中等倾斜角下，我们观察到 ν=7/2 FQHS 的增强。此外，在具有不对称电荷分布的阱中，当对称子带 ν(S)的 LL 填充因子等于 5/2 而反对称子带的填充因子为 1<ν(A)<2 时，会出现发展中的 FQHS。
