Moments and multiplets in moiré materials

Abstract The observation of strongly correlated states in moiré systems has renewed the conceptual interest magnetic with higher SU(4) spin symmetry, e.g., to describe Mott insulators where local moments are coupled spin–valley degrees freedom. Here, we discuss a numerical renormalization group scheme explore formation ordered and unconventional liquid at zero temperature based on pseudo-fermion representation. Our generalization conventional functional approach for $${{\mathfrak {s}}}{{\mathfrak {u}}}$$ s u (2) spins is capable treating diagonal off-diagonal couplings generic exchange Hamiltonians self-conjugate representation (4) algebra. To achieve proper efficiency, derive number symmetry constraints flow equations that significantly limit ordinary differential be solved. As an example system, investigate SU(2) $$_{\text {spin}}$$ spin $$\otimes $$ ⊗ U(1) {valley}}$$ valley model triangular lattice which exhibits rich phase diagram valley phases. Graphic