Topological characteristics of gap closing points in nonlinear Weyl semimetals

In this work we explore the effects of nonlinearity on three-dimensional topological phases. Of particular interest are the so-called Weyl semimetals, known for their Weyl nodes, i.e., pointlike topological charges which always exist in pairs and demonstrate remarkable robustness against general perturbations. It is found that the presence of onsite nonlinearity causes each of these Weyl nodes to break down into nodal lines and nodal surfaces at two different energies while preserving its topological charge. Depending on the system considered, additional nodal lines may further emerge at high nonlinearity strength. We propose two different ways to probe the observed nodal structures. First, the use of an adiabatic pumping process allows the detection of the nodal lines and surfaces arising from the original Weyl nodes. Second, an Aharonov-Bohm interference experiment is particularly fruitful to capture additional nodal lines that emerge at high nonlinearity.

Automated summary

This work investigates the effects of nonlinearity on three-dimensional topological phases, focusing on the behavior of Weyl nodes in Weyl semimetals. It is found that nonlinearity causes Weyl nodes to break down into nodal lines and surfaces while preserving their topological charge. Additional nodal lines may emerge at high nonlinearity. Adiabatic pumping and Aharonov-Bohm interference experiments are proposed as two methods to probe these observed nodal structures.