Electronic correlation effects in the stopping power of ions in 2D materials

The energy loss of charged projectiles in correlated materials is of prime relevance for plasma-surface interaction for which we have developed a nonequilibrium Green functions (NEGF) approach. A particularly interesting effect is the correlation induced increase of stopping power at low velocities [1]. However, NEGF simulations are possible only for short time durations, due to the unfavorable N_t³ scaling with the number of discretization time steps. The situation has changed radically with the recently developed G1-G2 scheme [2], which is based on the generalized Kadanaoff-Baym ansatz in combination with Hartree-Fock propagators, and allows to achieve linear scaling with N_t. This enhancement enables us to improve previous simulations by using better selfenergies [3], studying larger systems and by extending the simulation duration which gives access to slower projectiles. Finally, we will report further improvements of the G1-G2 scheme itself, by taking into account three-particle correlations.

[1] K. Balzer et al., Phys. Rev. Lett. 121, 267602 (2018)
[2] N. Schluenzen et al., Phys. Rev. Lett. 124, 076601 (2020)
[3] J.-P. Joost et al., Phys. Rev. B 101, 245101 (2020)