二维Su-Schrieffer-Heeger模型中的耦合各向异性弱拓扑态与Floquet混合奇偶性反常磁性
Coupled anisotropic weak topological states and Floquet mixed-parity altermagnetism in two-dimensional Su-Schrieffer-Heeger models
- School of Science, Hebei University of Technology（河北工业大学理学院）
- School of Science, Henan Agricultural University（河南农业大学理学院）
- Department of Physics, University of Antwerp（安特卫普大学物理系）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
该研究构建二维SSH模型，揭示t₁与t₂不等性是SSH拓扑态与AM序的起源，结合Floquet工程与RAD可实现混合奇偶性AM相，为相关研究提供理论平台。
AI中文摘要：
Su-Schrieffer-Heeger（SSH）拓扑系统与反常磁性（AM）态是凝聚态物理的两个重要研究领域，在单一体系中实现SSH晶格与AM相的耦合态仍具挑战性，而Floquet工程可改变这一现状。本研究采用紧束缚（TB）方法构建五个二维（2D）SSH模型，用以描述SSH弱拓扑态与AM序的耦合相，系统研究了二维SSH晶格中圆偏振光（CPL）与相对原子位移（RAD）作用下的能带结构演化、自旋分裂及拓扑相变。结果表明，跃迁参数t₁与t₂的不等性是SSH拓扑态与AM序的根本起源；对于二维非磁态，通过单胞选择可实现具有Zak相调控边缘态的各向异性弱拓扑态，与常规一维SSH模型类似；共线反铁磁态保持自旋简并能带结构与本征弱拓扑性质。此外，Floquet工程引入奇宇称p波AM相，RAD引入偶宇称d波AM相，结合二者效应可实现混合奇偶性（非奇非偶宇称）AM相，达成对自旋分裂光场与拓扑边缘态的同时调控；二维矩形SSH晶格中Floquet工程与RAD的物理机制同样源于t₁与t₂的不等性，该机制不仅可通过TB方法完全理解，还与二维碳基材料的第一性原理计算结果高度吻合。本研究为二维体系中耦合各向异性SSH弱拓扑态与多奇偶性AM序建立了有效的理论平台。
英文摘要：
Su-Schrieffer-Heeger (SSH) topological systems and altermagnetic (AM) states are two important research areas in condensed matter physics. Realizing the coupled states between the SSH lattices and AM phanse in a single syetem remains challenging. However, the Floquet engineering change it. Our work constructs five two-dimensional-(2D-) SSH models to describe the coupled phases of SSH weak topological state and AM order by tight-binding (TB) method. The evolution of band structures, spin-splitting, and topological phase transitions under the circularly polarized light (CPL) and relative atomic displacement (RAD) in 2D SSH lattices were systematically investigated. The results reveal that the inequality of hopping parameters (t1 and t2) serves as the fundamental origin of SSH topological states and AM order. For the 2D nonmagnetic state, anisotropic weak topological states with Zak phase governed edge states are realized by unit cell selection, similar to the conventional 1D SSH model. The collinear antiferromagnetic state preserves the spin-degenerate band structure and intrinsic weak topological properties. Furthermore, the Floquet engineering introduces the AM phase of odd-parity p-wave while the RAD introduces the AM phase of even-parity d-wave. By combining the two effects, the mixed-parity (non-odd/non-even parity) AM phase could be realized, achieving the simultaneous control of the light field of spin-splitting and topological edge states. The physical mechanisms of Floquet engineering and RAD for the 2D rectangular SSH lattice are also from the inequality of t1 and t2, which can be not only fully understand by the TB methods, but also in good agreement with the first-principle calculations of 2D carbon-based materials. This work establishes an effective theoretical platform for coupling anisotropic SSH weak topological states and AM orders with multi-parities in 2D systems.
