$P-V$ criticality and geometrothermodynamics of black holes with Born-Infeld type nonlinear electrodynamics

Abstract

In this paper, we take into account the black hole solutions of Einstein gravity with logarithmic and exponential forms of nonlinear electrodynamics. We consider $Λ$ as a dynamical pressure to study the analogy of the black holes with the Van der Waals system. We plot P-v, T-v and G-T diagrams and investigate the phase transition of adS black holes in the canonical ensemble. We study the nonlinearity effects of electrodynamics and see how the power of nonlinearity affects critical behavior. We also investigate the effects of dimensionality on the critical values and analyze its crucial role. Moreover, we show the changes in the universal ratio P_{c}v_{c}/T_{c} for variation of different parameters. In addition, we make a comparison between linear and nonlinear electrodynamics and show that the lowest critical temperature belongs to Maxwell theory. Also, we make some arguments regarding to how power of nonlinearity brings the system to Schwarzschild-like and Reissner-Nordstrom-like limitations. Next, we study the critical behavior in context of heat capacity. We show that critical behavior of system is similar to one in phase diagrams of extended phase space. We point out that phase transition points of the extended phase space only appear as divergencies of heat capacity. We also extend the study of phase transitions through GTD method. We introduce two new metrics and show that divergencies of TRS of the new metrics coincide with phase transitions. The characteristic behavior of these divergencies, hence critical points is exactly the one that is obtained in extended phase space and heat capacity. We also introduce a new method for obtaining critical pressure and horizon radius by considering denominator of the heat capacity. We show that there are several benefits that make this approach favorable comparing to other ones.