Chern-Textured Exciton Insulators with Valley Spiral Order in Moiré Materials

Abstract: We explore the phase diagrams of moir\'e materials in search of a new class of intervalley-coherent correlated insulating state: the Chern texture insulator (CTI). This phase of matter, proposed in a companion paper, breaks valley $U(1)$ symmetry in a nontrivial fashion wherein the valley order parameter is forced to texture in momentum space as a consequence of band topology. Using detailed Hartree-Fock studies, we establish that the CTI emerges as an energetically competitive intermediate-coupling ground state in several moir\'e systems which lack a twofold rotation symmetry that forbids the single-particle topology essential to the formation of the CTI valley texture.