Fig. 1: Crystal and magnetic structure of ErBr3.
From: Dipolar spin-waves and tunable band gap at the Dirac points in the 2D magnet ErBr3
a Crystal structure of ErBr3. Br− ions octahedrally coordinate Er3+ ions that form honeycomb layers stacked along the c-axis. b Honeycomb layer of Er3+ ions at z = 1/6 with ordered magnetic moments of 4.7 μB (black arrows) for a spin configuration given by angle Ψ = 0. The two trigonal sublattices of the honeycomb are shown as blue and red spheres. The crystallographic and magnetic unit cells are shown as black and green lines, respectively. c The classical magnetic ground state is continuously degenerate and the magnetic moments can be rotated in opposite direction by varying the angle Ψ. In panel c, Ψ = π/6.
