Institute for Theoretical Physics, University of Tübingen, Auf der Morgenstelle 14, 72076 Tübingen, Germany.
Phys Rev E. 2019 Nov;100(5-1):052602. doi: 10.1103/PhysRevE.100.052602.
We propose and study theoretically a colloidal system in two dimensions with attractive critical Casimir and repulsive magnetic dipole forces, wherein the strength of attraction and repulsion can be easily and independently tuned by adjusting the temperature and an external magnetic field, respectively. We expect this setup to be experimentally accessible and are confident that it can serve to deepen our understanding of the mechanisms behind microphase separation due to competing interactions. We develop a density functional theory for our model and present first results of our calculations in the form of a phase diagram for fixed temperature, but varying magnetic fields and bulk densities. For certain values of these parameters, we are able to confirm the existence of thermodynamically stable inhomogeneous density profiles in the bulk, such as parallel lamellar stripes, as well as clusters and voids on a hexagonal lattice.
我们提出并理论研究了二维胶体系统，其中存在有吸引力的临界 Casimir 力和排斥性的磁偶极力，通过分别调节温度和外加磁场，我们可以轻易且独立地调节吸引力和排斥力的强度。我们期望这个设置是可以实验实现的，并且有信心它可以帮助我们加深对竞争相互作用导致微相分离机制的理解。我们为模型开发了密度泛函理论，并以固定温度、变化磁场和体密度的相图形式呈现了我们计算的初步结果。对于这些参数的某些值，我们能够在体相中确认存在热力学稳定的非均匀密度分布，如平行层状条纹，以及六方格子上的团簇和空洞。
