Instability of the Novel 4D Charged Einstein-Gauss-Bonnet Anti de-Sitter Black Hole

We study the instability of the 4D charged Einstein-Gauss-Bonnet-AdS black holes by exploring the quasinormal modes of a charged massless scalar perturbation. We find that the instability is triggered by superradiance. The black hole becomes more unstable when increasing the Gauss-Bonnet coupling constant or the black hole charge. Meanwhile, increasing the AdS radius will make the black holes more stable. Moreover, we find that the system is more unstable for larger perturbation charge. The modes of multipoles are more stable than that of the monopole.