Charge density stabilised local electron spin pair states in insulating polymers
Charge density stabilised local electron spin pair states in insulating polymers
复制标题
绝缘聚合物中电荷密度稳定的局部电子自旋对态
DOI：
10.1063/1.4903751
复制
发表时间：
2014
影响因子：
3.2
通讯作者：
L. Dissado
中科院分区：
文献类型：
--
作者：
S. Serra;G. Montanari;L. Dissado
提出了一个模型，该模型解决了绝缘聚合物中局域电子态相对于可变电荷密度下的离域自由电子态的能量稳定性。该模型是使用有效哈密顿量导出的，用于计算大极化子和自旋配对双极化子中捕获的电子的总能量，其中包括当电荷密度超过无限稀释极限时发生的电荷之间的静电相互作用。利用根据聚乙烯实验数据确定的参数导出了各种电子态相对于电荷密度的相图，并且发现对于0.2 C/m3和∼2 C/m3之间的电荷密度，预测从稳定极化子形式的过量电荷到电荷 = 2且自旋数S = 0的双极子稳定状态的相变。这种转变与从低迁移率电荷传输到迁移率数量级高的脉冲形式的电荷传输的变化是一致的。
A model is presented that addresses the energy stability of localized electron states in insulating polymers with respect to delocalized free electron-like states at variable charge densities. The model was derived using an effective Hamiltonian for the total energy of electrons trapped in large polarons and spin-paired bipolarons, which includes the electrostatic interaction between charges that occurs when the charge density exceeds the infinite dilution limit. The phase diagram of the various electronic states with respect to the charge density is derived using parameters determined from experimental data for polyethylene, and it is found that a phase transition from excess charge in the form of stable polarons to a stable state of bipolarons with charge = 2 and spin number S = 0 is predicted for a charge density between 0.2 C/m3 and ∼2 C/m3. This transition is consistent with a change from low mobility charge transport to charge transport in the form of pulses with a mobility orders of magnitude highe...