Fig. 1: Moiré site degree of freedom.
From: Exciton Superposition across Moiré States in a Semiconducting Moiré Superlattice
a and b are schematics of 3 L WSe2/ 1 L WS2 moiré heterojunction device and natural trilayer WSe2 devices, respectively. Both devices are in a dual-gate configuration. c is the schematic of the WSe2/WS2 moiré superlattice, with three high symmetry points of C3 symmetry shown as hh, hX and hM. The naming convention of hh, hX and hM corresponds to aligning the hexagon center of the hole layer (WSe2) with the hexagon center (h), the chalcogen atom (X), and the metal atom (M) of the electron layer (WS2)20, which we also call as A, B and C moiré sites for convenience. A and B sites are energy minima for holes and behave as quantum dots that confine carriers and excitons. We use the holes for illustration in c, but the trapping of electrons and excitons will be similar.
