Observation of stacking engineered magnetic phase transitions within moiré supercells of twisted van der Waals magnets.

Recent demonstrations of moiré magnetism, featuring exotic phases with noncollinear spin order in the twisted van der Waals (vdW) magnet chromium triiodide CrI, have highlighted the potential of twist engineering of magnetic (vdW) materials. However, the local magnetic interactions, spin dynamics, and magnetic phase transitions within and across individual moiré supercells remain elusive. Taking advantage of a scanning single-spin magnetometry platform, here we report observation of two distinct magnetic phase transitions with separate critical temperatures within a moiré supercell of small-angle twisted double trilayer CrI.

Quantum Paraelastic Two-Dimensional Materials.

We study the elastic energy landscape of two-dimensional tin oxide (SnO) monolayers and demonstrate a transition temperature of T_{c}=8.5±1.8  K using ab initio molecular dynamics (MD) that is close to the value of the elastic energy barrier J derived from T=0  K density functional theory calculations.