Trace of altermagnetism in GdAlSi films: towards the 2D limit

Abstract

This study investigates altermagnetic effects in nanometer-thick GdAlSi films inherited from their bulk counterpart. This altermagnetic phenomenon is characterized by momentum-dependent spin splitting in collinear antiferromagnets, governed by specific symmetry. Using ab initio calculations, we analyze the magnetic and electronic properties of GdAlSi films with various thicknesses and surface terminations. We show that while non-relativistic spin splitting at high-symmetry points in the 2D Brillouin zone is evident in thicker films, it diminishes in ultra-thin films due to surface-induced symmetry breaking. Additionally, we demonstrate that carrier concentrations in monolayer GdAlSi films are higher than in the bulk, suggesting distinct electronic transport capabilities. These findings expand the altermagnetic materials landscape towards the nanometer-size limit essential for advanced spintronic applications.