Organic charged polaritons in the ultrastrong coupling regime

TL;DR

This paper demonstrates the creation of charged polaritons in the ultrastrong coupling regime using a hydrocarbon carbocation in a microcavity, revealing unique charge properties and potential for enhanced charge transport.

Contribution

It introduces a practical platform for studying charged polaritons in the ultrastrong coupling regime with significant charge fractions and ground state charge characteristics.

Findings

Achieved 41% Rabi splitting indicating ultrastrong coupling.

Polaritons carry a charge fraction of 0.55 e_0 and a large charge-to-mass ratio.

Ground state has about 1% of an elementary charge, suggesting enhanced charge transport.

Abstract

We embedded an all-hydrocarbon-based carbocation in a metallic microcavity that was tuned to resonance with an electronic transition of the carbocation. The measured Rabi splitting was 41% of the excitation energy, putting the system well into the ultrastrong coupling regime. Importantly, due to the intrinsic charge on the carbocation, the polaritons that form carry a significant charge fraction $0.55 e_0$ and a large charge-to-mass ratio ($\sim 2400 e_0 / m_0$). Moreover, the ground state of the ultrastrongly coupled system is calculated to carry about one percent of one elementary charge, implying a potentially enhanced charge transport across the molecules. These unique properties of our system, together with its convenient preparation, provide a practical platform to study charged polaritons in the ultrastrong coupling regime.