Current Transients in Graphene Electronics under Single-Particle Irradiation

Low-dimensional materials hold great promise in next-generation electronics. However, the performance of such devices is susceptible to external perturbations such as irradiation due to the high exposure of constituent atoms to the environment. Herein, real-time time-dependent density-functional theory at the tight-binding level extended to open systems for electrons and Ehrenfest dynamics for ions is developed and used to explore the effects of single-H irradiation on graphene electronics. The results show that the peak current displays distinct energy and site dependences, which are largely different from the dependences of the stopping powers. Charge-density analysis shows that the current transients are driven by delocalized plasmonic excitation, in contrast to localized electronic excitation, which plays a crucial role in the stopping power. The site dependence of the transient current is determined by the electron density at the irradiation site and the ionic charges. These findings highlight the roles of lattice discreteness and electronic structures of materials, which have been overlooked in previous studies based on theoretical formulations and semiempirical models. Using the insights gained from the calculations and the dataset constructed under typical space-irradiation conditions, the device responses of graphene nanoelectronics are modeled, laying the ground for device design in the space environment.