发表机构
Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México（墨西哥国立自治大学核科学研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文研究拓扑节线半金属中静电势垒的电荷输运，发现节线拓扑保护的克莱因隧穿，并推导线性和非线性电导表达式，揭示非线性增强和霍尔电流等输运特征，为器件应用提供途径。
AI 中文摘要
拓扑节线半金属是一种三维量子材料，其特征是能带交叉在动量空间中形成闭合环。在$\mathcal{PT}$对称实现中，这些节环在无自旋轨道耦合的情况下得以稳定存在，从而产生鼓面表面态和非常规输运响应。在本工作中，我们研究了包含有限静电势垒的节线半金属中的电荷输运，其中两个电极均由相同的平衡材料描述。通过求解相应的散射问题，我们表明，尽管存在扩展的节线色散，势垒上的透射表现出由节线拓扑保护的正常入射克莱因隧穿行为，这可追溯到贝里曲率诱导的动量锁定。利用Landauer-Büttiker形式，我们推导了线性和非线性电导的一般表达式，包括纵向和霍尔分量，并在零温和有限温度下对其进行了评估。我们的解析和数值结果阐明了电导对势垒高度和宽度以及$\mathcal{PT}$破缺质量项的依赖。我们识别了不同的输运区域，在这些区域中非线性贡献被强烈增强，横向霍尔电流出现，为节线拓扑提供了清晰的输运特征，并提出了器件应用的潜在途径。
英文摘要
Topological nodal-line semimetals are three-dimensional quantum materials characterized by band crossings that form closed loops in momentum space. In $\mathcal{PT}$-symmetric realizations, these nodal rings are stabilized in the absence of spin-orbit coupling, giving rise to drumhead surface states and unconventional transport responses. In this work, we study charge transport across a nodal-line semimetal containing a finite electrostatic barrier, with both leads described by the same equilibrium material. By solving the corresponding scattering problem, we show that the transmission across the barrier exhibits {Klein-tunneling behavior protected at normal incidence by the nodal topology}, despite the extended nodal-line dispersion, which can be traced back to Berry-curvature-induced momentum locking. Using the Landauer-Büttiker formalism, we derive general expressions for the linear and nonlinear conductances, including both longitudinal and Hall components, and evaluate them at zero and finite temperature. Our analytical and numerical results elucidate the dependence of the conductance on barrier height and width, as well as on a $\mathcal{PT}$-breaking mass term. We identify distinct transport regimes in which nonlinear contributions are strongly enhanced and transverse Hall currents emerge, providing clear transport signatures of nodal-line topology and suggesting potential routes toward device applications.
