$\mathbb{Z}_2$ gauge field and topological chirality from Umklapp scattering in twisted graphite
Abstract
Spinless systems exhibit unique topological characteristics compared to spinful ones, stemming from their distinct algebra. Without chiral interactions typically linked to spin, an intriguing yet unexplored interplay between topological and structural chirality may be anticipated. Here we show examples of spinless topological chirality solely from structural chirality in two types of twisted graphite. In a 3D helical structure, we find a chiral Weyl semimetal phase where bulk topology and chiral surface states are both determined by the screw direction. And in a 3D periodic structure formed with alternating twisting angle signs, a higherorder Dirac semimetal with chiral hinge states is discovered. Underlying these novel topological states is the Umklapp scattering that captures the chirality of the twisted interfaces, leading effectively to a signflipped chiral interlayer hopping, thereby introducing $\mathbb{Z}_2$ lattice gauge field that alters the symmetry algebra. Our findings point to a new pathway for engineering topological chirality.
 Publication:

arXiv eprints
 Pub Date:
 June 2024
 DOI:
 10.48550/arXiv.2406.08355
 arXiv:
 arXiv:2406.08355
 Bibcode:
 2024arXiv240608355C
 Keywords:

 Condensed Matter  Mesoscale and Nanoscale Physics;
 Condensed Matter  Materials Science
 EPrint:
 13 pages, 8 figures