Magnetic Properties of CrX₃ in Excited States

The CrX₃ (X=Cl,Br,I) are a new class of 2D magnetic semiconductor that show interesting properties such as ferromagnetism in monolayers, magneto-optical Kerr and Faraday effects, large tunnel magnetoresistance etc. The magnetism in these materials can be tuned through chemical doping or external field. In this talk we present our theoretical studies on the magnetic properties of the excited states of CrX₃ monolayer. Our calculations are carried out using density functional theory for different types of excitations on a cluster model of chromium trihalides. The cluster model of the monolayer is built with six Cr centers whereas a bilayer has two six-center Cr-halide clusters. These clusters are cut-outs of the bulk but are further passivated and optimized. We performed the three types of excited state calculations namely a) photo-induced excited state, b) excited states with different symmetry, and c) spin-flip excitons. The photo-induced single particle-hole excited states are being calculated with the perturbative delta-SCF method. The dipole and spin allowed transitions are selected to determine the possible set of excited states within the range of 1.5-3.5 eV. The calculated magnetic properties such as spin moments, exchange coupling constants, and magnetic anisotropy energies of these systems will be presented and discussed.<br/>This work is supported by the National Science foundation through grant no. DMR-2105109.