Analysis of Charge transfer doping in RuCl₃/semiconducting transition metal dichalcogenide heterostructures from first principles

The use of a-RuCl₃ has been proposed to achieve the emergence of novel phenomena at the interfaces of heterostructures formed with different two-dimensional materials. Here we rationalize the proximity induced changes in the electronic structure and charge transfer between RuCl₃ and semiconducting transition metal dichalcogenides (TMDs) MoTe₂ and WSe₂. To this end we use first principles calculations with the density functional theory (DFT) accounting for the on-site Coulomb interaction and spin-orbit coupling. Analysis using the Bader charges shows that owing to its high work function a-RuCl₃ becomes n-doped and its spin polarization decreases by approximately 0.2 /unit cell. In contrast, the TMD layers become p-doped (around 10¹³ cm^-2) but proximity effects do not produce spin polarization. We find that spin-orbit coupling plays an important role due its effects both in the a-RuCl₃ and the valence bands of MoTe₂ and WSe_2. Moreover, in-plane and out-of-plane strain considerably alters charge transfer. Results show that high work function metals may improve charge injection efficiency in these semiconducting TMD structures.