The multicritical behavior of the Blume-Capel model with infinite-range interactions is investigated by introducing quenched disorder in the crystal field $\Delta_{ i}$, which is represented by a superposition of two Gaussian distributions with the same width $\sigma$, centered at $\Delta_{ i} = \Delta$ and $\Delta_{ i} = 0$, with probabilities $p$ and $(1-p)$, respectively. A rich variety of phase diagrams is presented, and their distinct topologies are shown for different values of $\sigma$ and $p$. The tricritical behavior is analyzed through the existence of fourth-order critical points as well as how the complexity of the phase diagrams is reduced by the strength of the disorder.
Categories: cond-mat.stat-mech cond-mat.dis-nn