Nonlinear carrier dynamics in layered material heterojunctions

The hole transfer across MoS₂/WS₂ heterojunction was observed to be within 50fs at experiments.¹ The nonlinear dynamics of hole transfer process in MoS₂/WS₂ heterojunction was systematically studied with a two-level model. The critical phenomenon of maximal hole oscillation across MoS₂/WS₂ is proved to be dependent on multiple parameters, not limited to dipole transition matrix element Mz as shown in our previous work². Also, due to the periodic boundary condition, the previous model implicitly requires that all excitons are formed at the same time, however, this work shows that multiple excitons created in sequence by continuous wave laser will synchronize and reach the maximal hole transfer point at the same time. The critical phenomena of the nonlinear hole dynamics were explained with the theory of attraction of fixed point lines. Our work sheds light on a new direction of nonlinear carrier dynamics in two-dimensional material physics.

¹ X. Hong, J. Kim, S.-F. Shi, Y. Zhang, C. Jin, Y. Sun, S. Tongay, J. Wu, Y. Zhang, and F. Wang, Nat. Nanotechnol. 9, 682 (2014).
² H. Wang, J. Bang, Y. Sun, L. Liang, D. West, V. Meunier, and S. Zhang, Nat. Commun. 7, 11504 (2016).