论文标题
半导体人造石墨烯纳米结构的量子蒙特卡洛研究
Quantum Monte Carlo Study of Semiconductor Artificial Graphene Nanostructures
论文作者
论文摘要
Hubbard模型$ u/t $的半导体人工石墨烯纳米结构可为100阶，提供一个高度可控的平台来研究密切相关的量子多粒子相。 We use accurate variational and diffusion Monte Carlo methods to demonstrate a transition from antiferromagnetic to metallic phases for experimentally accessible lattice constant $a=50$ nm in terms of lattice site radius $ρ$, for finite sized artificial honeycomb structures nanopatterned on GaAs quantum wells containing up to 114 electrons.通过分析具有扶手椅边缘和带有锯齿形边缘的三角形薄片的六角形薄片的自旋自旋相关函数，我们显示了边缘类型，几何形状和电荷不均匀性会影响相变的陡度和交叉$ρ$值。对于三角形结构，金属 - 绝缘体的跃迁伴随着更平滑的边缘极化过渡。
Semiconductor artificial graphene nanostructures where Hubbard model parameter $U/t$ can be of the order of 100, provide a highly controllable platform to study strongly correlated quantum many-particle phases. We use accurate variational and diffusion Monte Carlo methods to demonstrate a transition from antiferromagnetic to metallic phases for experimentally accessible lattice constant $a=50$ nm in terms of lattice site radius $ρ$, for finite sized artificial honeycomb structures nanopatterned on GaAs quantum wells containing up to 114 electrons. By analysing spin-spin correlation functions for hexagonal flakes with armchair edges and triangular flakes with zigzag edges, we show that edge type, geometry and charge nonuniformity affect the steepness and the crossover $ρ$ value of the phase transition. For triangular structures, the metal-insulator transition is accompanied with a smoother edge polarization transition.
