Dynamical model for spin-crossover solids. II. Static and dynamic effects of light in the mean-field approach
Dynamical model for spin-crossover solids. II. Static and dynamic effects of light in the mean-field approach
复制标题
自旋交叉固体的动力学模型。
DOI：
10.1103/physrevb.62.14806
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发表时间：
2000
影响因子：
3.7
通讯作者：
F. Varret
中科院分区：
文献类型：
--
作者：
K. Boukheddaden;I. Shteto;B. Hôo;F. Varret
我们已经介绍了光激发的贡献，我们以前提出的动力学模型（见以前的论文），作为一个额外的长期在率转变，为了重现光诱导的热滞后效应，实验观察到的自旋交叉材料。得到了控制光下自旋交叉系统高自旋部分演化的运动方程组。平均场处理导致宏观主方程先前给出的唯象基础上。同时考虑HS→ LS（低自旋）和LS→ HS跃迁速率项，导出了一个通用的模型。该模型描述了光下的静态和动态特性。我们已经尽可能地分析研究了这个模型。光下的性质涉及两种性质不同的不稳定性：高温不稳定性，主要是熵驱动的，低温不稳定性，光诱导的。我们已经确定了这些不稳定性发生的条件，并研究了它们可能的崩溃。结合光致双稳态的可用数据讨论了所描述的现象：热滞环、光滞环和瞬态。计算了光致磁滞回线的动力学依赖性。
We have introduced a photoexcitation contribution in the dynamical model we previously presented (see previous paper), as an additional term in the rate transition, in order to reproduce the light induced thermal hysteresis effect, experimentally observed in the spin-crossover materials. The set of motion equations governing the evolution of the high-spin (HS) fraction of cooperative spin-crossover systems under light, is obtained. The mean-field treatment leads to a macroscopic master equation previously given on a phenomenological basis. With both the HS→ LS (low-spin) and LS→ HS transition rates terms, a model of general use is derived. This model describes the static and dynamic properties under light. We have investigated this model analytically, as far as possible. The properties under light involve two instabilities different in nature: the high-temperature instability, chiefly entropy driven, and the low-temperature one, light induced. We have determined the conditions for these instabilities to occur, and have examined their possible collapse. The described phenomena are discussed with respect to the available data on the photoinduced bistable regime: thermal hysteresis loops, optical hysteresis loops, and transient regimes. The kinetic dependence of the photoinduced hysteresis loops is calculated.