Atomically\nPrecise Control of Topological State Hybridization\nin Conjugated Polymers

Realization of topological\nquantum states in carbon nanostructures\nhas recently emerged as a promising platform for hosting highly coherent\nand controllable quantum dot spin qubits. However, their adjustable\nmanipulation remains elusive. Here, we report the atomically accurate\ncontrol of the hybridization level of topologically protected quantum\nedge states emerging from topological interfaces in bottom-up-fabricated\nπ-conjugated polymers. Our investigation employed a combination\nof low-temperature scanning tunneling microscopy and spectroscopy,\nalong with high-resolution atomic force microscopy, to effectively\nmodify the hybridization level of neighboring edge states by the selective\ndehydrogenation reaction of molecular units in a pentacene-based polymer\nand demonstrate their reversible character. Density functional theory,\ntight binding, and complete active space calculations for the Hubbard\nmodel were employed to support our findings, revealing that the extent\nof orbital overlap between the topological edge states can be finely\ntuned based on the geometry and electronic bandgap of the interconnecting\nregion. These results demonstrate the utility of topological edge\nstates as components for designing complex quantum arrangements for\nadvanced electronic devices.