Linear and nonlinear transport responses of topological nodal-line semimetals

L. E. Sosa-Arias; A. Martín-Ruiz

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arXiv · 2609.36664

Linear and nonlinear transport responses of topological nodal-line semimetals

L. E. Sosa-Arias·A. Martín-Ruiz

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Abstract

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.

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L. E. Sosa-Arias, A. Martín-Ruiz. 2026-09-29. Linear and nonlinear transport responses of topological nodal-line semimetals. https://arxiv.org/abs/2609.36664

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