Enhanced magnetometry with an electrically detected spin defect ensemble in silicon carbide

Spin defects in solid-state sensors are a highly promising platform for quantum sensing, a field with far-reaching applications in a variety of industries. Here, we investigate the magnetic sensitivity of a spin defect ensemble detected electrically in a silicon carbide pn-junction diode utilizing the hyperfine-induced spin-mixing effect observed in the vicinity of zero magnetic field. To enhance the baseline sensitivity, we employ above bandgap optical excitation to generate additional electron-hole pairs as well as a balanced detection scheme to reject common-mode noise, with an ultimate sensitivity of 30 nT/root Hz achieved. Both techniques are demonstrated to greatly enhance the magnetic sensitivity of the device by a total factor of similar to 24, paving the way toward sub-nanotesla magnetic field sensitivities with electrical detection.