Soba Alejandro, Tierno Pietro, Fischer Thomas M, Saguès Francesc
Departament de Química Física, Universitat de Barcelona, Martí i Franquès 1, Barcelona, Spain.
Phys Rev E Stat Nonlin Soft Matter Phys. 2008 Jun;77(6 Pt 1):060401. doi: 10.1103/PhysRevE.77.060401. Epub 2008 Jun 9.
We present a theoretical study of the recently observed dynamical regimes of paramagnetic colloidal particles externally driven above a regular lattice of magnetic bubbles [P. Tierno, T. H. Johansen, and T. M. Fischer, Phys. Rev. Lett. 99, 038303 (2007)]. An external precessing magnetic field alters the potential generated by the surface of the film in such a way to either drive the particle circularly around one bubble, ballistically through the array, or in triangular orbits on the interstitial regions between the bubbles. In the ballistic regime, we observe different trajectories performed by the particles phase locked with the external driving. Superdiffusive motion, which was experimentally found bridging the localized and delocalized dynamics, emerge only by introducing a certain degree of randomness into the bubbles size distribution.
我们对最近观察到的顺磁胶体粒子在磁泡规则晶格上方受到外部驱动的动力学机制进行了理论研究[P. 蒂耶尔诺、T. H. 约翰森和T. M. 菲舍尔，《物理评论快报》99，038303 (2007)]。外部进动磁场以这样一种方式改变薄膜表面产生的势，即要么驱动粒子围绕一个磁泡做圆周运动，要么使其沿阵列做弹道运动，要么在磁泡之间的间隙区域做三角形轨道运动。在弹道机制中，我们观察到与外部驱动锁相的粒子所执行的不同轨迹。超扩散运动是通过实验发现的连接局域化和非局域化动力学的现象，只有在磁泡尺寸分布中引入一定程度的随机性时才会出现。
