Charge state manipulation of qubits in diamond

Abstract

The nitrogen-vacancy (NV) centre in diamond is a promising candidate for a solid-state qubit. However, its charge state is known to be unstable, discharging from the qubit state NV− into the neutral state NV0 under various circumstances. Here we demonstrate that the charge state can be controlled by an electrolytic gate electrode. This way, single centres can be switched from an unknown non-fluorescent state into the neutral charge state NV0, and the population of an ensemble of centres can be shifted from NV0 to NV−. Numerical simulations confirm the manipulation of the charge state to be induced by the gate-controlled shift of the Fermi level at the diamond surface. This result opens the way to a dynamic control of transitions between charge states and to explore hitherto inaccessible states, such as NV+.

Increased negatively charged nitrogen-vacancy centers in fluorinated diamond

“…[6][7][8][9] Hydrogen is less electronegative than carbon, and thus a hydrogenterminated diamond surface exhibits a negative electron affinity. Adsorbed water layers on the surface accept electrons, and this electron transfer bends the surface bands upwards, resulting in hole accumulation at the surface and a primarily NV 0 population.…”

Nanoscale Sensing Using Point Defects in Single-Crystal Diamond: Recent Progress on Nitrogen Vacancy Center-Based Sensors

“…Stabilizing the NV − state close to the surface involves controlling the Fermi level in diamond [64][65][66][67]. The Fermi level, and consequently the NV − population, can be controlled via chemical functionalization of the surface [64,65,68,69] (see Figure 3a,b) by applying an electrolyte gate voltage [70] (see Figure 3c) using in-plane gate nanostructures [71] or via doping the diamond [67]. First, we consider the decrease in the NV − population of shallow NV centers close to a hydrogen (H)-terminated surface compared to an oxygenated surface [64,65].…”

“…For H-terminated diamond, electrolytic gate electrodes can directly control the Fermi level [70] (see Figure 3c). An increase in the NV − ensemble population was observed for high implantation dose and positive gate voltage.…”

Zinc Oxide Nanophotonics

“…ZnO nanoparticles that are coated with poly(methyl) methacrylate (PMMA) exhibited blinking behavior but did not bleach for more than 8 minutes. The emitters are influenced by the surface termination and can be switched on and off [56,57]. It has been analyzed that the mechanism of the blinking can originate from conversion from low probability transition state to a meta-stable dark state or from a photo-induced charge conversion of the defect to a charge exchange with other impurities that may act as charge traps.…”