无自旋轨道相互作用的谷与轨道调控二维陈绝缘体
Valley- and Orbital-Controlled 2D Chern Insulators Without Spin-orbit Interaction
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中文总结 AI 辅助
该研究通过理论分析含交错势和轨道耦合的二维晶格模型，发现无自旋轨道耦合时可实现轨道驱动的陈绝缘行为，明确了能隙关闭机制与拓扑窗口，为可调晶格系统的轨道工程提供了可行方向。
中文摘要 AI 辅助
我们对具有交错势（Δ）和与跳跃强度竞争的轨道耦合（λ）的二维晶格模型中轨道诱导的拓扑相变开展理论研究。通过调控这些参数，出现两种能隙关闭机制：当λ=±Δ时在K和K'点发生谷关闭，当λ=±√(Δ²+9t₀²)时在Γ点发生能隙关闭。它们的相互作用定义了一个拓扑窗口，其中贝里曲率局域在单个谷附近，产生量子化反常霍尔电导率（σₓᵧ=e²/h）和陈数（C=1）。这些结果证明了无自旋轨道耦合的轨道驱动陈绝缘行为，所得相图涵盖了从平庸相到拓扑相的转变，并为可调晶格系统中的轨道工程提供了实用途径。
英文摘要
We present a theoretical study of orbital-induced topological phase transitions in a two-dimensional lattice model with staggered potential $(Δ)$ and orbital coupling $(λ)$ competing with the hopping strength. By tuning these parameters, two gap-closing mechanisms emerge: valley closure at $\mathbf{K}$ and $\mathbf{K'}$ for $λ=\pmΔ$, and a $\mathbfΓ$-point closure at $λ=\pm\sqrt{Δ^2+9t_0^{2}}$. Their interplay defines a topological window in which the Berry curvature localizes near a single valley, yielding a quantized anomalous Hall conductivity ($σ_{xy}=e^{2}/h$) and Chern number ($C=1$). These results demonstrate orbital-driven Chern insulating behavior without spin-orbit coupling. The resulting phase diagram captures the transition from trivial to topological phases and suggests practical routes for orbital engineering in tunable lattice systems.
