Thermodynamic properties of novel black hole solutions in the Einstein–Born–Infeld-dilaton gravity theory

The exact solutions of coupled scalar, electromagnetic and gravitational field equations have been obtained in the framework of Einstein-dilaton gravity theory which is coupled to the Born–Infeld nonlinear electrodynamics. The solutions show that Einstein–Born–Infeld-dilaton gravity theory admits three novel classes of nonlinearly charged black hole solutions with the non-flat and non-AdS asymptotic behavior. Some of the solutions, in addition to the naked singularity, extreme and two-horizon black holes, produce one- and multi-horizon black holes too. The electric charge, mass and other thermodynamic quantities of the black holes have been calculated and it has been proved that they satisfy the standard form of the thermodynamical first law. The black hole local stability has been investigated by use of the canonical ensemble method. Noting the black hole heat capacity the points of type-one and type-two phase transitions and the locally stable black holes have been identified exactly. By use of the thermodynamic geometry, and noting the divergent points of the thermodynamic metric proposed by HEPM, it has been shown that the results of this method are consistent with those of canonical ensemble method. Global stability and Hawking–Page phase transition points have been studied by use of the grand canonical ensemble method and regarding the Gibbs free energy of the black holes. By calculating the Gibbs free energies, we characterized the ranges of horizon radii in which the black holes remain globally stable or prefer the radiation phase.