High-contrast optically detected magnetic resonance is a valuable property for reading out the spin of isolated defect colour centres at room temperature. Spin-active single defect centres have been studied in wide bandgap materials including diamond, SiC and hexagonal boron nitride, each with associated advantages for applications. We report the discovery of optically detected magnetic resonance in two distinct species of bright, isolated defect centres hosted in GaN. In one group, we find negative optically detected magnetic resonance of a few percent associated with a metastable electronic state, whereas in the other, we find positive optically detected magnetic resonance of up to 30% associated with the ground and optically excited electronic states. We examine the spin symmetry axis of each defect species and establish coherent control over a single defect’s ground-state spin. Given the maturity of the semiconductor host, these results are promising for scalable and integrated quantum sensing applications. 
                        more » 
                        « less   
                    This content will become publicly available on March 19, 2026
                            
                            GaN quantum emitters: basic physics, spin structure, and optically detected magnetic resonance (ODMR)
                        
                    
    
            GaN has recently been shown to host bright, photostable, defect single-photon emitters in the 600–700 nm wavelength range that are promising for quantum applications. Our studies have revealed the optical dipole structure, mechanisms associated with optical dipole dephasing, and the spin structure of these emitters. We have also discovered optically detected magnetic resonance (ODMR) in two distinct species of defects. In one group, we found negative optically detected magnetic resonance of a few percent associated with a metastable electronic state, whereas in the other, we found positive optically detected magnetic resonance of up to 30% associated with the ground and optically excited electronic states. We also established coherent control over a single defect’s ground-state spin. In this talk, we will present our results on the basic physics of these defects and also discuss the spin physics associated with the observed ODMR. 
        more » 
        « less   
        
    
                            - Award ID(s):
- 2240267
- PAR ID:
- 10580787
- Editor(s):
- Morkoç, Hadis; Fujioka, Hiroshi; Schwarz, Ulrich T
- Publisher / Repository:
- SPIE
- Date Published:
- ISBN:
- 9781510690035
- Page Range / eLocation ID:
- 8
- Format(s):
- Medium: X
- Location:
- San Francisco, United States
- Sponsoring Org:
- National Science Foundation
More Like this
- 
            
- 
            Abstract The recently discovered spin-active boron vacancy (V$${}_{{{{{{{{\rm{B}}}}}}}}}^{-}$$ ) defect center in hexagonal boron nitride (hBN) has high contrast optically-detected magnetic resonance (ODMR) at room-temperature, with a spin-triplet ground-state that shows promise as a quantum sensor. Here we report temperature-dependent ODMR spectroscopy to probe spin within the orbital excited-state. Our experiments determine the excited-state spin Hamiltonian, including a room-temperature zero-field splitting of 2.1 GHz and a g-factor similar to that of the ground-state. We confirm that the resonance is associated with spin rotation in the excited-state using pulsed ODMR measurements, and we observe Zeeman-mediated level anti-crossings in both the orbital ground- and excited-state. Our observation of a single set of excited-state spin-triplet resonance from 10 to 300 K is suggestive of symmetry-lowering of the defect system fromD3htoC2v. Additionally, the excited-state ODMR has strong temperature dependence of both contrast and transverse anisotropy splitting, enabling promising avenues for quantum sensing.more » « less
- 
            High-Contrast Plasmonic-Enhanced Shallow Spin Defects in Hexagonal Boron Nitride for Quantum Sensingnull (Ed.)The recently discovered spin defects in hexagonal boron nitride (hBN), a layered van der Waals material, have great potential in quantum sensing. However, the photoluminescence and the contrast of the optically detected magnetic resonance (ODMR) of hBN spin defects are relatively low so far, which limits their sensitivity. Here we report a record-high ODMR contrast of 46% at room temperature and simultaneous enhancement of the photoluminescence of hBN spin defects by up to 17-fold by the surface plasmon of a gold film microwave waveguide. Our results are obtained with shallow boron vacancy spin defects in hBN nanosheets created by low-energy He+ ion implantation and a gold film microwave waveguide fabricated by photolithography. We also explore the effects of microwave and laser powers on the ODMR and improve the sensitivity of hBN spin defects for magnetic field detection. Our results support the promising potential of hBN spin defects for nanoscale quantum sensing.more » « less
- 
            Radio frequency (RF) signals are frequently used in emerging quantum applications due to their spin state manipulation capability. Efficient coupling of RF signals into a particular quantum system requires the utilization of carefully designed and fabricated antennas. Nitrogen vacancy (NV) defects in diamond are commonly utilized platforms in quantum sensing experiments with the optically detected magnetic resonance (ODMR) method, where an RF antenna is an essential element. We report on the design and fabrication of high efficiency coplanar RF antennas for quantum sensing applications. Single and double ring coplanar RF antennas were designed with −37 dB experimental return loss at 2.87 GHz, the zero-field splitting frequency of the negatively charged NV defect in diamond. The efficiency of both antennas was demonstrated in magnetic field sensing experiments with NV color centers in diamond. An RF amplifier was not needed, and the 0 dB output of a standard RF signal generator was adequate to run the ODMR experiments due to the high efficiency of the RF antennas.more » « less
- 
            Incorporating magnetic ions into semiconductor nanocrystals has emerged as a prominent research field for manipulating spin-related properties. The magnetic ions within the host semiconductor experience spin-exchange interactions with photogenerated carriers and are often involved in the recombination routes, stimulating special magneto-optical effects. The current account presents a comparative study, emphasizing the impact of engineering nanostructures and selecting magnetic ions in shaping carrier–magnetic ion interactions. Various host materials, including the II–VI group, halide perovskites, and I–III–VI2 in diverse structural configurations such as core/shell quantum dots, seeded nanorods, and nanoplatelets, incorporated with magnetic ions such as Mn2+, Ni2+, and Cu1+/2+ are highlighted. These materials have recently been investigated by us using state-of-the-art steady-state and transient optically detected magnetic resonance (ODMR) spectroscopy to explore individual spin-dynamics between the photogenerated carriers and magnetic ions and their dependence on morphology, location, crystal composition, and type of the magnetic ion. The information extracted from the analyses of the ODMR spectra in those studies exposes fundamental physical parameters, such as g-factors, exchange coupling constants, and hyperfine interactions, together providing insights into the nature of the carrier (electron, hole, dopant), its local surroundings (isotropic/anisotropic), and spin dynamics. The findings illuminate the importance of ODMR spectroscopy in advancing our understanding of the role of magnetic ions in semiconductor nanocrystals and offer valuable knowledge for designing magnetic materials intended for various spin-related technologies.more » « less
 An official website of the United States government
An official website of the United States government 
				
			 
					 
					
