skip to main content

Title: Charge density stabilised local electron spin pair states in insulating polymers

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/m{sup 3} and ∼2 C/m{sup 3}. 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 higher that has been observed in several insulating polymers.
Authors:
 [1] ;  [1] ;  [2] ;  [3]
  1. Techimp SpA, Via Toscana 11/c, 40069 Zola Predosa, Bologna (Italy)
  2. (Italy)
  3. Department of Engineering, University of Leicester, Leicester LEI 7RH (United Kingdom)
Publication Date:
OSTI Identifier:
22402790
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 22; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CHARGE DENSITY; CHARGE TRANSPORT; ELECTRONS; HAMILTONIANS; MOBILITY; PHASE DIAGRAMS; PHASE TRANSFORMATIONS; POLARONS; POLYETHYLENES; PULSES; SPIN; STABILITY; TRAPPING