Transition metal qubits in 4H -silicon carbide: A correlated EPR and DFT study of the spin S=1 vanadium V

Abstract

Whereas intrinsic defects in silicon carbide (SiC) have been widely considered for qubit applications, transition metals in this material have not yet been recognized as alternative systems. We have investigated the magneto-optical properties of the V 3+ center in 4H -SiC by electron paramagnetic resonance (EPR) and photo-EPR spectroscopy in view of their possible application in quantum technology. We show that they fulfill all the requirements for such applications: a high-spin S = 1 ground state, optically induced ground-state spin polarization of more than 70%, long spin-lattice relaxation times of the order of a second, as well as associated zero-phonon photoluminescence emission lines in the range of 1.8 μm. Further, the zero-field splitting parameter D is temperature dependent and increases between T = 4 K and T = 292 K linearly with a rate of 440 kHz/K, allowing potential nanoscale temperature sensing. These properties make the vanadium acceptor an extremely promising candidate for qubit applications with optical properties in the telecommunication optical range.

Coherent Manipulation with Resonant Excitation and Single Emitter Creation of Nitrogen Vacancy Centers in 4H Silicon Carbide

“…Silicon carbide, however, is a mature industrial semiconductor material. ,,, Similarly to diamond, it can host isolated defects that can be harnessed as spin qubits in both the visible and the infrared spectral range. ,− In addition, the coherent manipulation of the electron spin of several defects, including the silicon vacancy, ,,, divacancy ,,,,− have been demonstrated, thus making defects in SiC appealing for quantum applications.…”

Spin Polarization, Electron–Phonon Coupling, and Zero-Phonon Line of the NV Center in 3C-SiC

“…Notably, the ZPL of NV in 3 C -SiC thus falls into the technologically relevant O-band. This makes it compatible with another recently emerged promising class of spin qubits in SiC, which also emits in the O-band, i.e., the vanadium center. , …”

“…This makes it compatible with another recently emerged promising class of spin qubits in SiC, which also emits in the O-band, i.e., the vanadium center. 24,25 It is remarkable that a nearly 100% spin polarization of the NV ground-state is obtained even though the excitation power in the high-resolution measurement at 1289 nm is very low (<1 μW). As the spin polarization observed in the CW EPR experiment is a competition between optical feeding in the | = m 0 S ground state and thermal relaxation (T 1 ), this is an indication of long spin−lattice relaxation times T 1 , which we have studied in the following in more detail.…”

Spin Polarization and Magnetic Moment in Silicon Carbide Grown by the Method of Coordinated Substitution of Atoms

“…In addition, it is desirable that these materials combine well with the standard materials of microelectronics, such as silicon Si, silicon carbide SiC, or III-V semiconductor compounds. This requirement is very important for scaling and ensuring the relationship between qubits [ 4 ]. The most studied solid-body spin is the negatively charged nitrogen-vacancy center (NV) in diamond [ 1 ].…”

“…The most studied solid-body spin is the negatively charged nitrogen-vacancy center (NV) in diamond [ 1 ]. In recent years, similar NV centers in SiC [ 5 , 6 ], as well as some other point defects based on silicon vacancies (V Si ) in SiC [ 4 , 7 ], have been intensely studied.…”