We propose a simple scheme to construct a model whose Fermi surface is comprised of crossing-line nodes. The Hamiltonian consists of a normal hopping term and an additional term which is odd under the mirror reflection. The line nodes appear along the mirror-invariant planes, where each line node carries the quantized Berry magnetic flux. We explicitly construct a model with the $N$-fold rotational symmetry, where the $2N$ line nodes merge at the north and south poles. When we apply photoirradiation along the $k_z$ axis, there emerge point nodes carrying the monopole charge $\pm N$ at these poles, while all the line nodes disappear. In this model, photoirradiation induces a topological phase transition from a crossing-line nodal semimetal to a multiple-Weyl semimetal, where the surface state turns from a drumhead state into a Fermi-arc state.

• Received 5 May 2017

DOI:https://doi.org/10.1103/PhysRevB.96.041205