Dyonic black holes from dimensional reduction of five-dimensional Einstein-Gauss-Bonnet gravity

We study the general black hole solutions of dimensionally reduced five-dimensional Einstein-Gauss-Bonnet gravity. The reduced theory contains gravity, electromagnetism and a scalar field, with nonlinear corrections to the action and nontrivial couplings. The solutions can be classified through mass and electric and magnetic charge. They present peculiar features with respect to the solutions of the standard Kaluza-Klein theory without Gauss-Bonnet corrections, like the existence of an extremal mass even in the neutral case. Also the thermodynamics is affected, for example, extremal black holes display nonvanishing temperature and entropy.