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arXiv · 2504.13280

Atomic-scale imaging and charge state manipulation of NV centers by scanning tunneling microscopy

Arjun Raghavan·Seokjin Bae·Nazar Delegan·F. Joseph Heremans·Vidya Madhavan
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Abstract

Nitrogen-vacancy (NV) centers in diamond are among the most promising solid-state qubit candidates, owing to their exceptionally long spin coherence times, efficient spin-photon coupling, room-temperature operation, and steadily advancing fabrication and integration techniques. Despite significant progress in the field, atomic-scale characterization and control of individual NV centers have remained elusive. In this work, we present a novel approach utilizing a conductive graphene capping layer to enable direct imaging and manipulation of $NV^{-}$ defects via scanning tunneling microscopy (STM). By investigating over 40 individual $NV^{-}$ centers, we identify their spectroscopic signatures and spatial configurations. Our dI/dV conductance spectra reveal the ground state approximately 300 meV below the Fermi level. Additionally, density-of-states mapping uncovers a two-lobed wavefunction aligned along the [111] crystallographic direction. Remarkably, we demonstrate the ability to manipulate the charge state of the NV centers from $NV^{-}$ to $NV^{0}$ through STM tip-induced gating. This work represents a significant advancement in the atomic-scale understanding and engineering of NV centers, paving the way for future quantum device development.

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Arjun Raghavan, Seokjin Bae, Nazar Delegan, F. Joseph Heremans, Vidya Madhavan. 2025-04-17. Atomic-scale imaging and charge state manipulation of NV centers by scanning tunneling microscopy. https://arxiv.org/abs/2504.13280

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