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We study the effect of strain on the physical properties of the nitrogen antisite-vacancy pair in hexagonal boron nitride (h-BN), a color center that may be employed as a quantum bit in a two-dimensional material. With group theory and ab initio analysis we show that strong electron–phonon coupling plays a key role in the optical activation of this color center. We find a giant shift on the zero-phonon-line (ZPL) emission of the nitrogen antisite-vacancy pair defect upon applying strain that is typical of h-BN samples. Our results provide a plausible explanation for the experimental observation of quantum emitters with similar optical properties but widely scattered ZPL wavelengths and the experimentally observed dependence of the ZPL on the strain.

with efficient locomotion in fluids. Particularly, in fields that require biosafety, these robots need to be biofriendly, biocompatible, and multifunctional. In recent years, cell membrane-coated microrobots were designed, which provided new possibilities for researchers to easily harness native biological functions. [10,11] Additionally, biological template-based microrobots, such as bacterium-based robots, [12,13] sperm-based robots, [14] and cell-based motors, [15,16] have extraordinary properties while maintaining their original functionality. By providing these biological robots with new characteristics, they can be propelled by an external field to achieve various functions. For example, researchers have created cell-based delivery systems with the property of low toxicity and immunogenicity including the red blood cells, [17] platelets, [18] stem cells, [19] immune cells, [20] and tumor cells [21] that could be controlled to achieve precise site-specific delivery with better treatment efficacy. [22,23] Recently, magnetically propelled microrobots have gained particular attention in the bioengineering field, since magnetic fields are capable of penetrating most materials with minimal interaction and are nearly harmless. [24][25][26][27][28][29] Inspiringly, these magnetically actuated robots demonstrate flexible controllability to navigate mazes and could be used to manipulate cells precisely. [30,31] Exposed to a magnetic field, different magneticdriven microrobots can be controlled simultaneously and wirelessly with high precision. Therefore, microrobotic swarm behavior emerges when a large number of magnetic robots are activated by an external field. Although a single microrobot can achieve complex tasks, the power of an individual is always limited. In nature, swarm behavior appears everywhere. Specifically, bees collaborate to work efficiently, ant colonies work together to carry larger objects, and a school of fish swim together to resist predators. In the microworld, a magnetically driven robot swarm is promising because the swarm has a flexible morphology, [32] can travel through narrow channels, [33,34] and can even be observed in real organisms. [35] However, the implementation of biocompatible and biofriendly robot swarms is still a challenge.Immune cells are widely known as excellent carriers for targeted drug delivery, [36][37][38][39][40] owing to their capability to be decorated with functional nanoparticles. For robotics and cell manipulation, using a single cell robot to manipulate other Border-nearing microrobots with self-propelling and navigating capabilities have promising applications in micromanipulation and bioengineering, because they can stimulate the surrounding fluid flow for object transportation. However, ensuring the biosafety of microrobots is a concurrent challenge in bioengineering applications. Here, macrophage template-based microrobots (cell robots) that can be controlled individually or in chain-like swarms are proposed, which can transport various objects. The cell rob...

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