Threshold phenomena under photoexcitation of spin-crossover materials with cooperativity due to elastic interactions

Miyashita, Seiji; Rikvold, Per Arne; Mori, Toshiyuki; Konishi, Yu; Nishino, Masamichi; Tokoro, Hiroko

doi:10.1103/physrevb.80.064414

Cited by 38 publications

(34 citation statements)

References 35 publications

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“…3 It has also been found that the long-range interaction affects dynamical properties. 8,9 In particular, the critical spinodal phenomena predicted by the mean-field theory are truly realized. This contrasts sharply with the case of short-range models, in which the spinodal phenomena occur as a crossover because nucleation-type fluctuations smear out the criticality.…”

Section: Introductionmentioning

confidence: 97%

Crossover between a short-range and a long-range Ising model

et al. 2011

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Recently, it has been found that an effective long-range interaction is realized among local bistable variables (spins) in systems where the elastic interaction causes ordering of the spins. In such systems, we generally expect both long-range and short-range interactions to exist. In the short-range Ising model, the correlation length diverges at the critical point. In contrast, in the long-range interacting model the spin configuration is always uniform and the correlation length is zero. As long as a system has nonzero long-range interactions, it shows criticality in the mean-field universality class, and the spin configuration is uniform beyond a certain scale. Here we study the crossover from the pure short-range interacting model to the long-range interacting model. We investigate the infinite-range model (Husimi-Temperley model) as a prototype of this competition, and we study how the critical temperature changes as a function of the strength of the long-range interaction. This model can also be interpreted as an approximation for the Ising model on a small-world network. We derive a formula for the critical temperature as a function of the strength of the long-range interaction. We also propose a finite-size scaling form for the spin correlation length at the critical point, which is finite as long as the long-range interaction is included, though it diverges in the limit of the pure short-range model. These properties are confirmed by extensive Monte Carlo simulations.

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Section: Introductionmentioning

confidence: 97%

Crossover between a short-range and a long-range Ising model

et al. 2011

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“…Starting from the Fokker-Plank equation (2) in the Itô representation, one can write the Fokker-Plank equation in the Stratonovich interpretation (A1) (see Appendix A). The stationary probability density P st (m) (7) is found from this Fokker-Planck equation (see Appendix B).…”

Section: Langevin Equation For a Finite-size Effect In An Ising-lmentioning

confidence: 99%

“…Recently it has been pointed out that, in some type of materials in which lattice structures of bistable states are different, a kind of effective long-range interaction due to the elastic interaction associated with the lattice distortion appears. Static and dynamical properties have been studied, and it has been found that the descriptions of the mean-field theory are exact for these systems [1,2]. With decrease of the number of components of the systems, the fluctuations increase.…”

Section: Introductionmentioning

confidence: 98%

Noise effects in a finite-size Ising-like model

2011

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We study finite-size effects on properties of stationary state and also transient process of a bistable system with long range interaction. We adopt an Ising-like model with infinite range interaction (Husimi-Temperlay model). In particular, we formulate this problem in light of the Langevin equation and investigate study the effects of various types of noises. We study characteristics of the probability of stationary state of a finite system and find that there exist two types of regions in the ordered state: the saturated region in which the maximum of the distribution locates at the maximum value of the Ising variable (±1) and the transient region in which the maximum of the distribution locates at a nonsaturated value. We introduce an additional type of noise that represents fluctuation due to direct coupling to the thermal bath. Finally we also study the finite-size effects on the dynamical aspect by studying the mean first-passage times.

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“…For example, Enachescu et al [10] presented interaction dependence after photoexcitation and studied cluster formation. The competition between light irradiation and self-accelerated relaxation has been considered in the paper by Miyashita et al [11]. Nicolazzi et al [12] investigated the light-induced phase-separation phenomenon in SC molecular solids using numerical simulations of a two-variable anharmonic model.…”

Section: Introductionmentioning

confidence: 98%