论文标题
Nagaoka Spin-Valley在硅量子点中订购
Nagaoka spin-valley ordering in silicene quantum dots
论文作者
论文摘要
我们研究了在硅烯中定义的一组量子点，该量子点具有旋转和山谷自由度的占主导地位。将原子的紧密结合和连续dirac近似适用于很少的电子系统，以寻求自发山谷的极化，这是由点间隧道和电子 - 电子相互作用驱动的，即山谷的山谷nagaoka nagaoka ferromagnetic序列的山谷，最近在GAAS Square Electrons中最近在Gaas Square Electrons中确定了三个多余的电子元素[P. DeHollain，{\ it等人}，自然{\ bf 579}，528（2020）]。我们发现，对于没有固有的自旋轨道耦合的哈密顿量，与具有交错电势的石墨烯相似 - 可以在一系列跨点间距中观察到地面山谷极化，前提是系统的旋转被外部磁场冻结。 valley间散射效应对于支持山谷极化地面状态的群集几何形状可以忽略不计。在存在石墨烯特征的强固有旋转轨道耦合的情况下，对于观察自旋和山谷中偏振的地面态的外部磁场是必需的。由于自旋轨道相互作用而引起的有效磁场产生了旋转式地下态中自旋和山谷同胞蛋白成分的完美反相关。
We study a cluster of quantum dots defined within silicene that host confined electron states with spin and valley degrees of freedom. Atomistic tight-binding and continuum Dirac approximation are applied for few-electron system in quest for spontaneous valley polarization driven by inter-dot tunneling and electron-electron interaction, i.e. a valley counterpart of itinerary Nagaoka ferromagnetic ordering recently identified in GaAs square cluster of quantum dots with three excess electrons [P. Dehollain, {\it et al.}, Nature {\bf 579}, 528 (2020)]. We find that for Hamiltonian without intrinsic-spin orbit coupling -- similar to the one of graphene with staggered potential -- the valley polarization in the ground-state can be observed in a range of inter-dot spacing provided that the spin of the system is frozen by external magnetic field. The inter-valley scattering effects are negligible for cluster geometry that supports the valley polarized ground-state. In presence of a strong intrinsic spin-orbit coupling that is characteristic to graphene no external magnetic field is necessary for observation of ground-state that is polarized in both spin and valley. The effective magnetic field due to the spin-orbit interaction produces a perfect anticorrelation of the spin and valley isospin components in the degenerate ground-state.
