High-Field Magnetoresistance of Organic Semiconductors

G. Joshi, M. Y. Teferi, S. Jamali, M. Groesbeck, J. van Tol, R. McLaughlin, Z. V. Vardeny, J. M. Lupton, H. Malissa, C. Boehme

Published 2018-04-25Version 1

The magneto-electronic field effects in organic semiconductors at high magnetic fields are described by field-dependent mixing between singlet and triplet states of weakly bound charge carrier pairs due to small differences in their Land\'e g-factors that arise from the weak spin-orbit coupling in the material. In this work, we corroborate theoretical models for the high-field magnetoresistance of organic semiconductors, in particular of diodes made of the conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) at low temperatures, by conducting magnetoresistance measurements along with multi-frequency continuous-wave electrically detected magnetic resonance experiments. The measurements were performed on identical devices under similar conditions in order to independently assess the magnetic field-dependent spin-mixing mechanism, the so-called {\Delta}g mechanism, which originates from differences in the charge-carrier g-factors induced by spin-orbit coupling.