The microstructure and Ruppeiner geometry of charged anti-de Sitter black holes in Gauss-Bonnet gravity: from the critical point to the triple point

Understand

Ruppeiner geometry has been successfully applied in the study of the black hole microstructure by combining with the small-large black hole phase transition, and the potential interactions among the molecular-like constituent degrees of freedom are uncovered.

• In this paper, we will extend the study to the triple point, where three black hole phases coexist acting as a typical feature of black hole systems quite different from the small-large black hole phase transition.
• For the six-dimensional charged Gauss-Bonnet anti-de Sitter black hole, we thoroughly investigate the swallow tail behaviors of the Gibbs free energy and the equal area laws.
• After obtaining the black hole triple point in a complete parameter space, we exhibit its phase structures both in the pressure-temperature and temperature-horizon radius diagrams.