Electrocaloric effect in bulk and low-dimensional ferroelectrics from first principles
Electrocaloric effect in bulk and low-dimensional ferroelectrics from first principles
复制标题
DOI：
10.1103/physrevb.78.052103
复制
发表时间：
2008-08
影响因子：
3.7
通讯作者：
S. Prosandeev;I. Ponomareva;L. Bellaiche
中科院分区：
文献类型：
--
作者：
S. Prosandeev;I. Ponomareva;L. Bellaiche
基于第一性原理的有效哈密顿量与非平衡态分子动力学相结合，以确定在铁电体中的电场诱导的温度变化。因此，（i）所施加的场可以是具有宽频率范围的ac性质，（ii）可以研究bulksandnanostructures（具有均匀或高度不均匀的偶极配置），以及（iii）可以揭示各种现象对电热效应的影响。该方案产生的电热系数与测量非常一致，强烈依赖于场诱导的体积inbulks的变化。在交流电场作用下，量子点也出现了一种不寻常的现象。
First-principles-based effective Hamiltonians are combined with nonequilibrium molecular dynamics to determine the electric-field-induced change in temperature in ferroelectrics. As a result, (i) the applied field can be ac in nature with a wide frequency range, (ii) bulksandnanostructures (with homogeneous or highly inhomogeneous dipolar configurations) can be investigated, and (iii) the influence of various phenomena on the electrocaloric effect can be revealed. This scheme yields an electrocaloric coefficient in excellent agreement with measurement and that strongly depends on the field-induced variation of volume inbulks. An unusual phenomenon is also reported in dots under ac fields.