Speaker
Description
POSTER PRESENTATION
The electronic structure of a moiré material reflects both the valley and orbital character
of its parent layers and the symmetry of the twisted bilayer. First-principles calculations
of twisted WSe₂ show that Γ- and K-derived minibands retain distinct orbital character,
which helps explain their different responses to strain and out-of-plane pressure.
Changes in valley ordering then switch the valence-band edge between triangular and
honeycomb lattice models. Parent-band information thus helps identify the active low-
energy model and interpret its tunability. Twisted SnS reveals a complementary role of
moiré symmetry: a nonsymmorphic screw rotation, together with time-reversal symmetry,
protects two-dimensional hourglass fermions in the spin-orbit-coupled bands. Such
symmetry-enforced connectivity broadens the model classes available to moiré
quantum-simulation platforms. The combined roles of parent-band character and moiré
symmetry motivate a systematic investigation beyond individual material families. We
therefore construct a first-principles atlas of more than 600 relaxed twisted bilayers
spanning hexagonal, square, rectangular and oblique lattices. Combining band unfolding
with symmetry-representation analysis, the atlas connects parent valleys and orbitals to
the effective lattice, orbital content and band connectivity. It organizes material
candidates by the microscopic degrees of freedom and symmetry constraints relevant to
correlated and topological physics.