Thermodynamics of three-dimensional black holes via charged particle absorption

We have shown that changes occur in a (2 + 1)-dimensional charged black hole by adding a charged probe. The particle increases the entropy of the black hole and guarantees the second law of thermodynamics. The first law of thermodynamics is derived from the change in the black hole mass. Using the particle absorption, we test the extremal black hole and find out that the mass of the extremal black hole increases more than the electric charge. Therefore, the outer horizon of the black hole still exists. However, the extremal condition becomes non-extremal. (C) 2016 The Authors. Published by Elsevier B.V.