Department of Physics and Astronomy, Rice University, Houston, Texas 77251, USA.
Phys Rev Lett. 2010 Apr 23;104(16):166801. doi: 10.1103/PhysRevLett.104.166801. Epub 2010 Apr 21.
We report on the magnetotransport (including tilt fields) around Landau level filling factor nu=5/2 in a high-purity modulation-doped GaAs/AlGaAs quantum well with twice the electron density of standard samples. A quantized 5/2 Hall plateau is observed at B approximately = 10 T, with an activation gap approximately 125 mK; the plateau can persist up to approximately 25 degree tilt field. This finding is discussed in the context of a proposed Moore-Read Pfaffian (or anti-Pfaffian) wave function being a possible ground state at 5/2. The tilt fields induce a background resistance at 5/2 that could be either isotropic or anisotropic, depending simply on the in-plane magnetic field direction with respect to the GaAs crystalline axis. Such data indicate a substantial coupling between the 5/2 collective phases and the GaAs crystal.
我们报告了在具有两倍于标准样品电子密度的高纯度调制掺杂 GaAs/AlGaAs 量子阱中，朗道能级填充因子 $\nu=5/2$ 附近的磁输运（包括倾斜场）。在约 B=10T 的磁场下观察到了量子化的 5/2 Hall 平台，激活能隙约为 125mK；该平台可以持续到约 25 度的倾斜场。这一发现是在提出的 Moore-Read Pfaffian（或反 Pfaffian）波函数可能是 5/2 的基态的背景下讨论的。倾斜场在 5/2 处诱导出背景电阻，其可以是各向同性的，也可以是各向异性的，这取决于相对于 GaAs 晶轴的平面内磁场方向。这些数据表明 5/2 集体相和 GaAs 晶体之间存在很大的耦合。
