Far-from-equilibrium growth of magnetic thin films with Blume-Capel impurities

MAZZITELLO, K; CANDIA, J; E. V. ALBANO

PHYSICAL REVIEW E - STATISTICAL PHYSICS, PLASMAS, FLUIDS AND RELATED INTERDISCIPLINARY TOPICS

APS

Lugar: New York; Año: 2015 vol. 91 p. 42118 - 42125

1063-651X

We investigate the irreversible growth of (2 + 1)-dimensional magnetic thin films. The spin variable can adoptthree states (si = ±1,0), and the system is in contact with a thermal bath of temperature T . The depositionprocess depends on the change of the configuration energy, which, by analogy to the Blume-Capel Hamiltonianin equilibrium systems, depends on Ising-like couplings between neighboring spins (J ) and has a crystal field(D) term that controls the density of nonmagnetic impurities (si = 0). Once deposited, particles are not allowedto flip, diffuse, or detach. By means of extensive Monte Carlo simulations, we obtain the phase diagram inthe crystal field vs temperature parameter space. We show clear evidence of the existence of a tricritical pointlocated at Dt/J = 1.145(10) and kBTt/J = 0.425(10), which separates a first-order transition curve at lowertemperatures from a critical second-order transition curve at higher temperatures, in analogy with the previouslystudied equilibrium Blume-Capel model. Furthermore, we show that, along the second-order transition curve,the critical behavior of the irreversible growth model can be described by means of the critical exponents ofthe two-dimensional Ising model under equilibrium conditions. Therefore, our findings provide a link betweenwell-known theoretical equilibrium models and nonequilibrium growth processes that are of great interest formany experimental applications, as well as a paradigmatic topic of study in current statistical physics.