Department of Physics, Tohoku University, Sendai 980-8578, Japan.
Phys Rev Lett. 2012 Sep 14;109(11):116805. doi: 10.1103/PhysRevLett.109.116805. Epub 2012 Sep 12.
Scanning tunneling spectroscopy is used to study the real-space local density of states of a two-dimensional electron system in a magnetic field, in particular within higher Landau levels. By Fourier transforming the local density of states, we find a set of n radial minima at fixed momenta for the nth Landau levels. The momenta of the minima depend only on the inverse magnetic length. By comparison with analytical theory and numerical simulations, we attribute the minima to the nodes of the quantum cyclotron orbits, which decouple in a Fourier representation from the random guiding center motion due to disorder. Adequate Fourier filtering reveals the nodal structure in real space in some areas of the sample with relatively smooth potential disorder.
扫描隧道谱被用于研究磁场中二维电子系统的实空间局域态密度，特别是在更高的朗道能级内。通过对局域态密度进行傅里叶变换，我们在第 n 个朗道能级处找到一组固定动量的 n 个径向极小值。这些极小值的动量仅取决于磁场的倒数长度。通过与解析理论和数值模拟进行比较，我们将这些极小值归因于量子回旋轨道的节点，这些节点由于无序而在傅里叶表示中与随机引导中心运动解耦。适当的傅里叶滤波揭示了在具有相对平滑的势无序的样品的某些区域中的实空间中的节点结构。
