Stability of Cauchy horizon in a charged de-Sitter spacetime with dark matter

Abstract The violation of strong cosmic censorship (SCC) in RNdS black holes by a minimally coupled neutral massless scalar field has recently been discovered. This paper investigates the stability of the Cauchy horizon of a spherically charged de-Sitter black hole surrounded by dark matter under perturbations from a massless scalar field. Our results show that SCC can also be destroyed in the nearly extremal region, regardless of the presence of dark matter. However, the existence of dark matter can mitigate the extent of SCC violation, particularly when the cosmological constant and dark matter energy density are both small. Notably, the violation region of SCC as a function of the dark matter state parameter does not exhibit a simple monotonic decrease, suggesting that the influence of dark matter on SCC is not straightforward and may be complex.