Lifshitz transitions and hybrid Weyl points in RbAg5Se3

We explore the topological phase transitions of RbAg5Se3 using first-principles calculations in combination with the maximally localized Wannier function method. Our computations reveal that the type-II Dirac cone in RbAg5Se3 protected by the inversion and time-inversion (PT) symmetry in addition to the C4z rotation symmetry can be regulated to type-III and type-I Dirac points by applying strain along the [001] direction. More interestingly, when the inversion symmetry is lifted by intercalating a Pt atom into the unit cell, sixteen hybrid Weyl points emerge accompanied by the Fermi arcs connecting the adjacent Brillouin zones and surface states on the (010) surface. The type-II Weyl point has the chirality of 1, while the type-I Weyl point has the chirality of −1. Our work suggests that RbAg5Se3 serves as a promising platform for study of topological phases transitions with curious transport phenomena.