Year: 2026
Type: preprint
Abstract: We investigate a two-dimensional $p_xp_y$ square-net tight-binding model with two sublattices and introduce a symmetry-informed, momentum-dependent spin-orbit coupling (SOC) with a finite-range real-space hopping representation. Its two components jointly gap the nodal line, while one breaks time-reversal symmetry, producing a Chern-insulating phase with an occupied band Chern number $C=2$. Nanoribbon calculations reveal edge-localized states traversing this gap, with two net chiral modes per edge. We further show that the conserved spin sectors are unitarily equivalent and therefore have equal Chern numbers, ruling out a nontrivial time-reversal-protected $\mathbb{Z}_2$ phase within this ansatz. Our results establish a phenomenological route to Chern topology in square-net two-dimensional systems and clarify the symmetry constraints governing the accessible insulating phases.
Source: arXiv (Cornell University)
Institution: University of Arkansas at Fayetteville
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: U.S. Department of Energy
OpenAlex ID: W7223940173