P-V criticality in the extended phase space of charged f(R) black holes in AdS space-time

The P-V criticality and phase transition in the extended phase space of charged f(R) black holes in Anti-de Sitter (AdS) space-time are studied, where the cosmological constant appears as a dynamical pressure and its conjugate quantity is a thermodynamic volume of the black holes. We take into account three-dimensional and higher-dimensional black holes of the f(R) theory coupled to a conformally invariant Maxwell (CIM) field and find that for a f(R) black hole in three-dimensional space-time, critical behavior cannot occur; for a f(R) black hole in higher-dimensional space-time, no P-V criticality occurs in n = 8 dimensions either, while P-V criticality and the small-black-hole/large-black-hole phase transition appears in n = 12 dimensions. It is shown that the f(R) correction affects the phase transition as well as the critical temperature, volume and pressure. In addition, we also discuss the critical exponents at the critical point for the f(R) black hole in n space-time dimensions and show that they are the same as those in the van de Waals liquid-gas system. Copyright (C) EPLA, 2016