Triple points and phase diagrams in the extended phase space of charged Gauss-Bonnet black holes in AdS space

We study the triple points and phase diagrams in the extended phase space of the charged Gauss-Bonnet black holes in d-dimensional anti-de Sitter space, where the cosmological constant appears as a dynamical pressure of the system and its conjugate quantity is the thermodynamic volume of the black holes. Employing the equation of state T = T(v, P), we demonstrate that the information of the phase transition and behavior of the Gibbs free energy are potential encoded in the T - v ( T - r(h)) line with fixed pressure P. We get the phase diagrams for the charged Gauss-Bonnet black holes with different values of the charge Q and dimension d. The result shows that the small/large black hole phase transitions appear for any d, which is reminiscent of the liquid/gas transition of a Van der Waals type. Moreover, the interesting thermodynamic phenomena, i.e., the triple points and the small/intermediate/large black hole phase transitions are observed for d = 6 and Q is an element of (0.1705, 0.1946).