In a step toward atomic-resolution nuclear magnetic resonance (NMR), researchers have detected and controlled a single carbon-13 nuclear spin in a two-dimensional (2D) material for the first time. The researchers from Purdue University created spin defects in ultrathin hexagonal boron nitride (hBN) and used optically detected magnetic resonance (ODMR) to extract hyperfine-level detail at the atomic scale.
“We’re interested in developing technologies that can detect and analyze a single molecule,” said Tongcang Li, lead author and professor of physics and electrical engineering at Purdue.
Traditional NMR spectroscopy is limited by its need for large molecular ensembles and relatively coarse resolution. By contrast, the Purdue approach employs spin defects in atomically thin hBN – created via carbon-13 ion implantation – as quantum sensors that can interact with nearby nuclei in a single molecule deposited on the surface.
Using high-sensitivity ODMR, the team identified three distinct defect types based on hyperfine splitting, some reaching 300 MHz. These defects enabled room-temperature detection of both S = 1 and S = 1/2 spin states – crucial for initializing and reading out nuclear spin states via electron-nuclear coupling.
In collaboration with the University of Wisconsin-Madison, the researchers used density functional theory to confirm the atomic structure of the defects. Optically detected nuclear magnetic resonance (ODNMR) provided additional detail, revealing two-peaked resonance patterns corresponding to specific defect types and magnetic environments.
This research demonstrates the potential of 2D quantum sensors not only for atomic-resolution NMR, but also for storing quantum information and enhancing the sensitivity of quantum devices. “Our work advances the understanding of spin defects in hexagonal boron nitride and provides a pathway to enhance quantum sensing with nuclear spins as quantum memories,” Li said.
With further optimization, this platform could one day enable true single-molecule NMR spectroscopy and fuel new applications across materials science, chemistry, and quantum technology.
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