Thermal stability and local atomic registries of moire excitons in 2D WSe2/MoSe2 heterostructures

In two-dimensional (2D) heterostructures (HSs) the stacking of single layers of 2D materials with a non-zero relative angle between their respective lattice orientations produces a moire superlattice, which, in turn, results in the formation of a moire potential. The subjects of our study are moire excitons (MXs), the electron-hole bound pairs confined in the minima of said potential. In this article, we investigate MXs in a WSe2/MoSe2 HS through continuous wave and time-resolved micro-photoluminescence (mu -PL) and magneto-mu -PL. We analyze the PL spectra of the HS at different temperatures and for different photogenerated charge carrier densities and find that MXs dominate the interlayer exciton (IX) spectrum at low temperatures and turn into free IXs for temperatures higher than 120 K. We also studied the exciton magnetic moment of MXs and concluded that the MX band presents contributions from different local atomic registries.