Quantum units from the topological engineering of molecular graphenoids

Abstract

Robustly coherent spin centers that can be integrated into devices are a key ingredient of quantum technologies. Vacancies in semiconductors are excellent candidates, and theory predicts that defects in conjugated carbon materials should also display long coherence times. However, the quantum performance of carbon nanostructures has remained stunted by an inability to alter the sp2-carbon lattice with atomic precision. Here, we demonstrate that topological tailoring leads to superior quantum performance in molecular graphene nanostructures. We unravel the decoherence mechanisms, quantify nuclear and environmental effects, and observe spin-coherence times that outclass most nanomaterials. These results validate long-standing assumptions on the coherent behavior of topological defects in graphene and open up the possibility of introducing controlled quantum-coherent centers in the upcoming generation of carbon-based optoelectronic, electronic, and bioactive systems.

Synthetic Tailoring of Graphene Nanostructures with Zigzag‐Edged Topologies: Progress and Perspectives

“…Moreover, the introduction of nonplanarity by the incorporation of nonhexagonal rings into sp 2 -carbon frameworks may provide an alternative pathway. [140][141][142][143][144] Only by overcoming the stability obstacle will further integration of these exotic materials in carbon-based nanoelectronic devices become possible.…”

Combining Molecular Spintronics with Electron Paramagnetic Resonance: The Path Towards Single-Molecule Pulsed Spin Spectroscopy

“…The method of choice to investigate spin phenomena is EPR. Using advanced techniques, we can decouple the spins from the nuclear spin bath yielding competing quantum coherence times nearly reaching milliseconds, as it has been shown for graphenoids [282,283]. Addressing single molecules via EPR can then happen using magnetic scanning tunnelling tips [284].…”

Spiers Memorial Lecture : Carbon nanostructures by macromolecular design – from branched polyphenylenes to nanographenes and graphene nanoribbons

“…207 Pulsed EPR spectroscopy of 88 measured in the group of Lapo Bogani provides the spin lattice and coherence times as characteristic features of the high-spin structure. 208 The significance of high coherence times will be reconsidered for spin-bearing GNRs below. An example of a diradical structure that follows from topological frustration rather than from five-or seven-membered defects is the case of 90, the so-called Clar goblet with the shape of a bowtie, which was introduced by Roman Fasel and Xinliang Feng ( Figure 15A).…”