Electrical detection of nuclear spins via silicon vacancies in silicon carbide at room temperature

Abstract

Color centers in wide-bandgap semiconductors, including diamond and silicon carbide (SiC), are attractive systems for quantum information and quantum sensor devices with excellent spin properties at room temperature. In addition, nuclear spins in crystals are expected to serve as the quantum memory and to enhance the sensitivity of quantum sensors with the combination with color centers as a result of an extremely long spin coherence time. Although the spin state of both color centers and nuclear spins coupled through hyperfine interactions is usually optically read out, an electrical readout technique is important for miniaturizing and integrating devices. In the present study, we report the electrical detection of silicon vacancy (V2) centers in 4H-SiC by photocurrent-detected magnetic resonance (PDMR) using a frequency-sweep technique. We electrically observe the spin coherence of the V2 centers and clearly resolve the hyperfine splitting of the electron spin signal for the V2 centers coupled with next-nearest-neighbor ²⁹Si atoms. In addition, we apply PDMR to electron–nuclear double resonance (PD-ENDOR) to detect nuclear magnetic resonance of ²⁹Si at room temperature and find that this method can resolve nuclear spins coupled with neighboring electron spins in the V2 centers. The realization of PD-ENDOR is expected to be a critical step toward the development of electrically driven integrated quantum devices.