Combining the synthetic tunability of molecular compounds with the optical selection rules of transition metal dichalcogenides (TMDC) that derive from spin-valley coupling could provide interesting opportunities for the readout of quantum information. However, little is known about the electronic and spin interactions at such interfaces and the influence on spin-valley relaxation. In this work, vanadyl phthalocyanine (VOPc) molecular layers are thermally evaporated on WSe2 to explore the effect of molecular layer thickness on excited-state spin-valley polarization. The thinnest molecular layer supports an interfacial state which destroys the spin-valley polarization almost instantaneously, whereas a thicker molecular layer results in longer-lived spin-valley polarization than the WSe2 monolayer alone. The mechanism appears to involve a tightly-bound species at the molecule/TMDC interface that strengthens exchange interactions and is largely avoided in thicker VOPc layers that isolate electrons from WSe2 holes.
@article{arxiv.2310.06979,
title = {Modulating spin-valley relaxation in WSe$_2$ with variable thickness VOPc layers},
author = {Daphné Lubert-Perquel and Byeong Wook Cho and Alan J. Philips and Young Hee Lee and Jeffrey L. Blackburn and Justin C. Johnson},
journal= {arXiv preprint arXiv:2310.06979},
year = {2025}
}