We compute the mass and the temperature of third order Lovelock black holes
with negative Gauss-Bonnet coefficient α2<0 in anti-de Sitter space and
perform the stability analysis of topological black holes. When k=−1, the
third order Lovelock black holes are thermodynamically stable for the whole
range r+. When k=1, we found that the black hole has an intermediate
unstable phase for D=7. In eight dimensional spacetimes, however, a new phase
of thermodynamically unstable small black holes appears if the coefficient
α~ is under a critical value. For D≥9, black holes have
similar the distributions of thermodynamically stable regions to the case where
the coefficient α~ is under a critical value for D=8. It is
worth to mention that all the thermodynamic and conserved quantities of the
black holes with flat horizon don't depend on the Lovelock coefficients and are
the same as those of black holes in general gravity.Comment: 15 pages, 22 figure