Spin density wave order in interacting type-I and type-II Weyl semimetals

Abstract

Weyl semimetals, featuring massless linearly dispersing chiral fermions in three dimensions, provide an excellent platform for studying the interplay of electronic interactions and topology, and exploring new correlated states of matter. Here, we examine the effect of a local repulsive interaction on an inversion-symmetry breaking Weyl semimetal model, using cluster dynamical mean field theory and variational cluster approximation methods. Our analysis reveals a continuous transition from the gapless Weyl semimetal phase to a gapped spin density wave ordered phase at a critical value of the interaction, which is determined by the band structure parameters. Further, we introduce a finite tilt in the linear dispersion and examine the corresponding behavior for a type-II Weyl semimetal model, where the critical interaction strength is found to be significantly diminished, indicating a greater susceptibility towards interactions. The behavior of different physical quantities, such as the double occupancy, the spectral function and the Berry curvature associated with the Weyl nodes are obtained in both the semimetallic and the magnetically ordered states. Finally, we provide an interaction-induced phase diagram for the Weyl semimetal model, as a function of the tilt parameter.