Strong Coupling of Microwave Photons to Antiferromagnetic Fluctuations in an Organic Magnet

Matthias Mergenthaler,Amber L Thompson,Edward A Laird,Jennifer J Le Roy,Peter J Leek,Stephen J Blundell,Arzhang Ardavan,Lapo Bogani,G Andrew D Briggs,Fernando Luis,Junjie Liu,Tom Lancaster,Natalia Ares

doi:10.1103/physrevlett.119.147701

Matthias Mergenthaler, Amber L Thompson + Show 11 more

Open Access

https://doi.org/10.1103/physrevlett.119.147701

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Abstract

Coupling between a crystal of di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium radicals and a superconducting microwave resonator is investigated in a circuit quantum electrodynamics (circuit QED) architecture. The crystal exhibits paramagnetic behavior above 4K, with antiferromagnetic correlations appearing below this temperature, and we demonstrate strong coupling at base temperature. The magnetic resonance acquires a field angle dependence as the crystal is cooled down, indicating anisotropy of the exchange interactions. These results show that multispin modes in organic crystals are suitable for circuit QED, offering a platform for their coherent manipulation. They also utilize the circuit QED architecture as a way to probe spin correlations at low temperature.

Highlights

Coupling between a crystal of di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium radicals and a superconducting microwave resonator is investigated in a circuit quantum electrodynamics architecture
The crystal exhibits paramagnetic behavior above 4 K, with antiferromagnetic correlations appearing below this temperature, and we demonstrate strong coupling at base temperature
Characteristic interaction strengths in organic magnets are such that these materials typically approach or undergo a phase transition only at mK temperatures [19,20,21,22], making them difficult to study with conventional electron spin resonance (ESR)

Summary

Introduction

Coupling between a crystal of di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium radicals and a superconducting microwave resonator is investigated in a circuit quantum electrodynamics (circuit QED) architecture. The magnetic resonance acquires a field angle dependence as the crystal is cooled down, indicating anisotropy of the exchange interactions. Characteristic interaction strengths in organic magnets are such that these materials typically approach or undergo a phase transition only at mK temperatures [19,20,21,22], making them difficult to study with conventional electron spin resonance (ESR).

Results

Conclusion