标题： 自旋相变在由腔光子控制的量子环阵列中的研究 显示英文标题

标题： Spin-phase transition in an array of quantum rings controlled by cavity photons

摘要： 我们模拟了一个二维正方形阵列或横向超晶格中的量子环，在外部垂直均匀磁场中的自旋相变。电子系统被放置在一个圆形圆柱形远红外光子腔中，该腔具有单一的圆形对称光子模式。我们的数值结果表明，每个量子环中二维电子气体的自旋序可以受到电子-光子耦合强度和光子能量的影响或控制。电子之间的库仑相互作用由自旋密度泛函方法描述，但顺磁和抗磁电子-光子相互作用则通过截断多体福克空间中的组态相互作用形式进行建模，并在密度泛函方法的每次迭代步骤中进行更新。在没有外部电磁脉冲的情况下，这种自旋相变会在环的轨道磁化中重复出现。强电子-光子相互作用可以抑制这种自旋相变。此外，在动力学计算中发现了自旋构型的波动，其中系统通过一种专门设计的时间依赖方案被激发，以强调抗磁电子-光子相互作用。 显示英文摘要

摘要： We model a spin-phase transition in a two-dimensional square array, or a lateral superlattice, of quantum rings in an external perpendicular homogeneous magnetic field. The electron system is placed in a circular cylindrical far-infrared photon cavity with a single circularly symmetric photon mode. Our numerical results reveal that the spin ordering of the two-dimensional electron gas in each quantum ring can be influenced or controlled by the electron-photon coupling strength and the energy of the photons. The Coulomb interaction between the electrons is described by a spin-density functional approach, but the para- and the diamagnetic electron-photon interactions are modeled via a configuration interaction formalism in a truncated many-body Fock-space, which is updated in each iteration step of the density functional approach. In the absence of external electromagnetic pulses this spin-phase transition is replicated in the orbital magnetization of the rings. The spin-phase transition can be suppressed by a strong electron-photon interaction. In addition, fluctuations in the spin configuration are found in dynamical calculations, where the system is excited by a time-dependent scheme specially fit for emphasizing the diamagnetic electron-photon interaction.