Tunable in-plane anisotropy of quasiparticles in twisted MoS₂/CrOCl heterostructures

Twisted isotropic-anisotropic van der Waals heterostructures provide a platform for controlling the electronic and phononic properties of 2D materials and inducing in-plane anisotropy in some isotropic materials. Herein, angle-resolved polarized Raman spectroscopy and photoluminescence spectroscopy are used to investigate the induced in-plane anisotropy of the quasiparticles in the twisted MoS2/CrOCl heterostructures. Both the phonons ( E(g)(2 MoS2 )and A(g)(1 MoS2) modes) and excitons (A and B excitons) in MoS2 represent a strong in-plane orientation dependence, and the maximum intensities are along the [100](CrOCl). The induced anisotropy ratios of phonons vary continuously in the range from 1.22 to 1.13 for the E(g)(2 MoS2 )mode and 1.15 to 1.09 for the A(g)(1 MoS2) mode with changing twisted angles, which originate from the anisotropic carrier mobility induced by the localized charge distribution from the anisotropic CrOCl substrates, and are further tuned by the uniaxial local limit of charge carriers caused by 1D moir & eacute; pattern. Our findings provide a way to controllably regulate the induced in-plane optical anisotropy in heterostructures.