Spin-quenching in molecule-transition-metal-dichalcogenide heterostructure through inverse proximity effect

TL;DR

This paper demonstrates how the inverse proximity effect in molecule-TMD heterostructures can tune exciton energies and spin states, enabling control over magnetic and optical properties for quantum applications.

Contribution

It introduces a novel mechanism for spin-quenching via inverse proximity effect in molecule-TMD heterostructures, enhancing exciton functionality and tunability.

Findings

Charge transfer character of molecular excitons

Tunable magnetic moments via molecular orientation

Conditions for bright, well-separated interlayer excitons

Abstract

A functional heterostructure is central to integrated circuitry in quantum photonics, optoelectronics, neuromorphic computing, spintronics, and straintronics. Recently, heterostructures combining 2D magnets and nonmagnetic transition metal dichalcogenides (TMDs) have been explored. In these, electron and hole wavefunctions are localized in 2D magnets but delocalized in TMDs. When combined, a proximity induced magnetic inter layer exciton can emerge, with energy differing by 20 to 30 meV from intra layer excitons and being two orders of magnitude darker, making it hard to detect and functionalize. Using a high fidelity ab initio many body diagrammatic approach, we show that functionality can be significantly enhanced in a transition metal molecule TMD interface. The molecular exciton exhibits charge transfer character and is extended, unlike the localized Frenkel excitation in 2D magnets. Moreover, the degree of localization and magnetic moment can be tuned by varying the molecular orientation relative to the TMD. This changes the proximity to the magnetic ion, altering screening and enabling a pathway to quench the ion's spin moment. This inverse proximity effect tunes the energies, spin states, and brightness of molecular and inter layer magnetic excitons, a mechanism absent in 2D magnet TMD systems. We also identify conditions under which the interlayer exciton becomes well separated and brighter than intra layer excitons, making it promising for protocols that probe and manipulate magnetic excitonic states.