Trigonal Bipyramidal V<sup>3+</sup> Complex as an Optically Addressable Molecular Qubit Candidate
Majed S. Fataftah, Sam L. Bayliss, Daniel W. Laorenza, Xiao-Ling Wang, Brian T. Phelan, C. Blake Wilson, Peter J. Mintun, Berk Kovos, Michael R. Wasielewski, Songi Han, Mark S. Sherwin, D. D. Awschalom, Danna E. Freedman
Abstract
Synthetic chemistry enables a bottom-up approach to quantum information science, where atoms can be deterministically positioned in a quantum bit or qubit. Two key requirements to realize quantum technologies are qubit initialization and read-out. By imbuing molecular spins with optical initialization and readout mechanisms, analogous to solid-state defects, molecules could be integrated into existing quantum infrastructure. To mimic the electronic structure of optically addressable defect sites, we designed the spin-triplet, V3+ complex, (C6F5)3trenVCNtBu (1). We measured the static spin properties as well as the spin coherence time of 1 demonstrating coherent control of this spin qubit with a 240 GHz electron paramagnetic resonance spectrometer powered by a free electron laser. We found that 1 exhibited narrow, near-infrared photoluminescence (PL) from a spin-singlet excited state. Using variable magnetic field PL spectroscopy, we resolved emission into each of the ground-state spin sublevels, a crucial component for spin-selective optical initialization and readout. This work demonstrates that trigonally symmetric, heteroleptic V3+ complexes are candidates for optical spin addressability.