NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy.
Phys Rev Lett. 2012 Jun 15;108(24):246801. doi: 10.1103/PhysRevLett.108.246801. Epub 2012 Jun 13.
Transport experiments provide conflicting evidence on the possible existence of fractional order within integer quantum Hall systems. In fact, integer edge states sometimes behave as monolithic objects with no inner structure, while other experiments clearly highlight the role of fractional substructures. Recently developed low-temperature scanning probe techniques offer today an opportunity for a deeper-than-ever investigation of spatial features of such edge systems. Here we use scanning-gate microscopy and demonstrate that fractional features were unambiguously observed in every integer quantum Hall constriction studied. We present also an experimental estimate of the width of the fractional incompressible stripes corresponding to filling factors 1/3, 2/5, 3/5, and 2/3. Our results compare well with predictions of the edge-reconstruction theory.
输运实验对整数量子霍尔系统中分数阶的存在提供了相互矛盾的证据。事实上，整数边缘态有时表现为没有内部结构的整体物体，而其他实验则清楚地突出了分数子结构的作用。最近开发的低温扫描探针技术为更深入地研究这种边缘系统的空间特征提供了机会。在这里，我们使用扫描门显微镜，并证明在研究的每个整数量子霍尔限制中都明确观察到了分数特征。我们还给出了对应于填充因子 1/3、2/5、3/5 和 2/3 的分数不可压缩条纹的宽度的实验估计。我们的结果与边缘重构理论的预测很好地吻合。
