All-Optical dc Nanotesla Magnetometry Using Silicon Vacancy Fine Structure in Isotopically Purified Silicon Carbide

Abstract

We uncover the fine structure of a silicon vacancy in isotopically purified silicon carbide (4H-28 SiC) and reveal not yet considered terms in the spin Hamiltonian, originated from the trigonal pyramidal symmetry of this spin-3/2 color center. These terms give rise to additional spin transitions, which would be otherwise forbidden, and lead to a level anticrossing in an external magnetic field. We observe a sharp variation of the photoluminescence intensity in the vicinity of this level anticrossing, which can be used for a purely all-optical sensing of the magnetic field. We achieve dc magnetic field sensitivity better than 100 nT/ √ Hz within a volume of 3 × 10 −7 mm 3 at room temperature and demonstrate that this contactless method is robust at high temperatures up to at least 500 K. As our approach does not require application of radiofrequency fields, it is scalable to much larger volumes. For an optimized light-trapping waveguide of 3 mm 3 the projection noise limit is below 100 fT/ √ Hz.

Vector Magnetometry Using Silicon Vacancies in4H-SiC Under Ambient Conditions

“…Thus, our methods are suitable for sub-mT dc vector magnetometry. When B 0 ∼ h2D=gμ B , the suggested methods may not be useful because of complex spectra arising due to interactions among spin sublevels [56][57][58]. At high magnetic fields, e.g., B 0 ∼ 300 mT, two transitions f 21 and f 43 are well observable at every orientation as experimentally reported [17,43].…”

Identification of Si-vacancy related room-temperature qubits in 4H silicon carbide

“…The V2 line in 4H -SiC [4] and the V2 and V3 lines in 6H -SiC [13] are sufficiently strong to observe their corresponding electron spin via optically detected magnetic resonance (ODMR) measurements at room temperature. In particular, it has been demonstrated that the V2 color center in 4H -SiC can be used for magnetometer [17][18][19][20] and nanoscale thermometer [21] applications and as a room-temperature maser [14].Today, it is widely accepted that V1-V3 PL lines and T V1 -T V3 electron paramagnetic resonance (EPR) signals in 4H -and 6H -SiC are related to spin-3/2 negatively charged silicon vacancies [22][23][24][25]. On the other hand, the actual microscopic configuration of these vacancy related centers is still debated.…”

“…The V2 line in 4H -SiC [4] and the V2 and V3 lines in 6H -SiC [13] are sufficiently strong to observe their corresponding electron spin via optically detected magnetic resonance (ODMR) measurements at room temperature. In particular, it has been demonstrated that the V2 color center in 4H -SiC can be used for magnetometer [17][18][19][20] and nanoscale thermometer [21] applications and as a room-temperature maser [14].…”

Оптический Квантовый Термометр С Субмикронным Разрешением, Основанный На Явлении Кросс-Релаксации Спиновых Уровней

“…Недавно нами были обнаружены вакансионные спиновые центры в карбиде кремния (SiC), в которых спиновые уровни с S = 3/2 селективно заселяются под дейст-вием оптического излучения в ближнем ИК-диапазоне, совместимом с полосой прозрачности волоконной оптики и биологических систем, и предложен способ использования оптически детектируемого магнит-ного резонанса (ОДМР) для измерения магнитных и температурных полей [2][3][4][5][6][7][8][9]. Был предложен оптический квантовый термометр [8], ко-торый использовал физическое явление сильного изменения интенсив-ности фотолюминесценции (ФЛ) (photoluminescence, PL) в магнитных полях, близких к точке антипересечения спиновых подуровней центров с S = 3/2 (level anticrossing -LAC) в возбужденном состоянии, которые характеризовались сильной зависимостью расщепления тонкой структуры (zero-field splitting) от температуры [7].…”