Spin Berry phase in the Fermi-arc states

Imura Ken-Ichiro

Takane Yositake

Physical Review B

An unusual electronic property of a Weyl semimetallic nanowire is revealed. Its band dispersion exhibits multiple subbands of partially flat dispersion, originating from the Fermi-arc states. Remarkably, the lowest energy flat subbands bear a finite size energy gap, implying that electrons in the Fermi-arc surface states are susceptible to the spin Berry phase. This is shown to be a consequence of spin-to-surface locking in the surface electronic states. We verify this behavior and the existence of the spin Berry phase in the low-energy effective theory of Fermi-arc surface states on a cylindrical nanowire by deriving the latter from a bulk Weyl Hamiltonian. We point out that in any surface state exhibiting a spin Berry phase π, a zero-energy bound state is formed along a magnetic flux tube of strength Φ0/2=hc/(2e). This effect is highlighted in a surfaceless bulk system pierced by a dislocation line, which shows a 1D chiral mode along the dislocation line.

Physics [ 420 ]

eng

American Physical Society

(c) 2011 American Physical Society

[ISSN] 1098-0121

[DOI] 10.1103/PhysRevB.84.245415

[NCID] AA11187113

[DOI] http://dx.doi.org/10.1103/PhysRevB.84.245415