Exotic Weyl semimetal, emergent Fermi surface, and Lifshitz phase transition

Abstract

Weyl semimetals (WSMs) with paired Weyl points in momentum space have attracted much attention in the past decade, and materials for this phase and the exotic Fermi arcs at their surface have been realized, in which the topology can be found in a finite momentum interval. Here we suggest a four-band model for WSM with two Weyl points in the ${k}_{z}$ axis, yet with totally different Fermi arcs at the surfaces. It exhibits a large anomalous Hall conductivity in the bulk, and large density of state on their surface. We analytically and numerically demonstrate the topological properties of this model from the dispersion, ${k}_{z}$-dependent Chern number, Fermi arc states, and dual topological phase. Furthermore, we investigate the effects of the magnetic field on the unusual Fermi arcs and find two emergent Fermi surfaces. Their combination can lead to diverse Lifshitz phase transitions when the thickness of the slab is decreased. The change of Fermi surfaces can be detected by the quantum oscillation, in which the contributions from a different number of closed Fermi surfaces can lead to different magnetotransport behaviors. We expect this model can stimulate the search for its realization in condensed matter physics and quantum simulating platforms.