Detection of nonlinear magnetic resonance phenomena using spin-dependent charge carrier recombination currents through deuterated poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV)

Experimental data have recently confirmed theoretical predictions of nonlinear magnetic resonant strong-drive phenomena using spin-dependent electronic transitions in organic semiconductor thin-films as observable [1]. Strong magnetic resonant drive occurs when the magnitude of the driving field is on the order or in excess of static Zeeman fields. We have extended this current-based spin measurement technique by a lock-in detection scheme that filters radiation-induced, spin-independent current signals from spin-dependent current signals, and we have used this to study resonant electron magnetic dipole transitions within a deuterated layer of poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV), similar to previous studies that were conducted without the lock-in scheme [1, 2]. The data obtained with this increased measurement accuracy confirms excellent agreement of the experimentally observed Bloch-Siegert shift for magnetic dipole transitions with theory. [1] Jamali, S., Mkhitaryan, V.V. et al. Nat Commun 12, 465 (2021). [2] Waters, D., Joshi et al. Nature Phys 11, 910–914 (2015).