Microscopic theory of OMAR based on kinetic equations for quantum spin correlations

Abstract

The correlation kinetic equation approach is developed that allows describing spin correlations in a material with hopping transport. The quantum nature of spin is taken into account. The approach is applied to the problem of the bipolaron mechanism of organic magnetoresistance (OMAR) in the limit of large Hubbard energy and small applied electric field. The spin relaxation that is important to magnetoresistance is considered to be due to hyperfine interaction with atomic nuclei. It is shown that the lineshape of magnetoresistance depends on short-range transport properties. Different model systems with identical hyperfine interaction but different statistics of electron hops lead to different lineshapes of magnetoresistance including the two empirical laws $H^2/(H^2+H_0^2)$ and $H^2/(|H|+H_0{)}^2$ that are commonly used to fit experimental results.

References in corpus (5)

• The effects of spin-spin interactions on magnetoresistance in disordered organic semiconductors
• Hopping charge transport in organic materials
• Universal power law decay of spin polarization in double quantum dot
• Memory effects, two color percolation, and the temperature dependence of Mott's variable range hopping
• The system of correlation kinetic equations and the generalized equivalent circuit for hopping transport

Cited by in corpus (3)

• Dynamic polarization of electron spins in indirect band gap (In,Al)As/AlAs quantum dots in weak magnetic field: experiment and theory
• Electric current noise in mesoscopic organic semiconductors
• Dynamic spin polarization in organic semiconductors with intermolecular exchange interaction