The spin-Dicke effect in OLED magnetoresistance

Waters, D. P., Joshi, G., Kavand, M., Limes, M. E., Malissa, H., Burn, P. L., Lupton, J. M. and Boehme, C. (2015) The spin-Dicke effect in OLED magnetoresistance. Nature Physics, 11 11: 910-914. doi:10.1038/nphys3453


Author Waters, D. P.
Joshi, G.
Kavand, M.
Limes, M. E.
Malissa, H.
Burn, P. L.
Lupton, J. M.
Boehme, C.
Title The spin-Dicke effect in OLED magnetoresistance
Journal name Nature Physics   Check publisher's open access policy
ISSN 1745-2473
1745-2481
Publication date 2015-11-03
Year available 2015
Sub-type Article (original research)
DOI 10.1038/nphys3453
Open Access Status Not Open Access
Volume 11
Issue 11
Start page 910
End page 914
Total pages 5
Place of publication London, United Kingdom
Publisher Nature Publishing Group
Language eng
Formatted abstract
Pairs of charge-carrier spins in organic semiconductors constitute four-level systems that can be driven electromagnetically1. Given appropriate conditions for ultrastrong coupling2—weak local hyperfine fields Bhyp, large magnetic resonant driving fields B1 and low static fields B0 that define Zeeman splitting—the spin-Dicke effect, a collective transition of spin states, has been predicted3. This parameter range is challenging to probe by electron paramagnetic resonance spectroscopy because thermal magnetic polarization is negligible. It is accessed through spin-dependent conductivity that is controlled by electron–hole pairs of singlet and triplet spin-permutation symmetry without the need of thermal spin polarization4. Signatures of collective behaviour of carrier spins are revealed in the steady-state magnetoresistance of organic light-emitting diodes (OLEDs), rather than through radiative transitions. For intermediate B1, the a.c.-Zeeman effect appears. For large B1, a collective spin-ensemble state arises, inverting the current change under resonance and removing power broadening, thereby offering a unique window to ambient macroscopic quantum coherence.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2016 Collection
School of Chemistry and Molecular Biosciences
 
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