Random Blume-Capel model on a cubic lattice: First-order inverse freezing in a three-dimensional spin-glass system

We present a numerical study of the Blume-Capel model with quenched disorder in three dimensions. The phase diagram is characterized by spin-glass/paramagnet phase transitions of both first and second order in the thermodynamic sense. Numerical simulations are performed using the exchange Monte Carlo algorithm, providing clear evidence for inverse freezing. The main features at criticality and in the phase-coexistence region are investigated. The whole inverse freezing transition appears to be first order. The second-order transition appears to be in the same universality class as the Edwards-Anderson model. The nature of the spin-glass phase is analyzed by means of the finite-size scaling behavior of the overlap distribution functions and the four-spin real-space correlation functions. Evidence for a replica-symmetry-breaking-like organization of states is provided.