Cuervo-Reyes Eduardo
Swiss Federal Laboratories for Materials Science and Technology (Empa), Materials meet life, Dübendorf, 8600, Switzerland.
Sci Rep. 2016 Jul 1;6:29021. doi: 10.1038/srep29021.
Materials response to electric or magnetic fields is often dominated by the dynamics of dipoles in the system. This is for instance the case of polar dielectrics and many transition metal compounds. An essential and not yet well understood fact is that, despite their structural diversity, dielectric solids exhibit a striking universality of frequency and time responses, sharing many aspects with the behaviour of spin-glasses. In this article I propose a stochastic approach to dipole dynamics within which the "universal frequency response" derives naturally with Debye's relaxation mechanism as a special case. This formulation reveals constraints to the form of the relaxation functions, which are essential for a consistent representation of the dynamical slowing-down at the spin-glass transition. Relaxation functions with algebraic-, and exponential-tails, as well as damped oscillations, are shown to have a unified representation in which the stable limit of the distribution of waiting-times between dipole flips determines the present type of dynamics.
材料对电场或磁场的响应通常由系统中偶极子的动力学主导。例如，极性电介质和许多过渡金属化合物就是这种情况。一个基本但尚未得到充分理解的事实是，尽管介电固体结构多样，但它们在频率和时间响应方面表现出惊人的普遍性，与自旋玻璃的行为有许多共同之处。在本文中，我提出了一种偶极子动力学的随机方法，在这种方法中，“通用频率响应”作为一种特殊情况自然地从德拜弛豫机制中推导出来。这种表述揭示了弛豫函数形式的限制，这对于在自旋玻璃转变时动态减速的一致表示至关重要。具有代数尾、指数尾以及阻尼振荡的弛豫函数被证明具有统一的表示形式，其中偶极子翻转之间等待时间分布的稳定极限决定了当前的动力学类型。
