Finite size effect on the Fermi arc surface states in Weyl semimetal

Abstract

A hallmark of the Weyl semimetal is the presence of two gapless Fermi arc surface states between two Weyl nodes. The Fermi arc surface states give rise to quantum anomalous Hall effect. Through analytically solving a finite size Weyl semimetal slab, we find that the two surface states can couple together producing a gap in the spectrum of Fermi arc surface states. Due to the finite size effect, the quantum anomalous Hall effect of Fermi arc states will be modified. This effect is anticipated to be measurable in experiment.