As information devices continue to evolve toward miniaturization and high integration, conventional sensor technologies encounter significant physical limitations when scaled down to nanoscale dimensions. Quantum point contacts (QPCs) emerge as a promising solution, offering atomic-scale tunability, exceptional sensitivity to single-electron charges, and seamless compatibility with low-dimensional material platforms. Leveraging quantum effects such as quantum conductance, QPC-based sensing techniques harness the unique electronic behaviors at atomic scales, paving the way for next-generation ultra-miniaturized electronic devices. This review provides an in-depth analysis of QPCs, elucidating their fundamental physical properties, including quantum conductance and shot noise, while exploring traditional manipulation methods such as mechanical control, gate voltage adjustments, and the emerging nanoionics approach. Furthermore, the review highlights the application of QPCs in quantum sensing for molecular adsorption, light and heat detection, and their potential in information storage and quantum computing. Despite their promise, challenges related to stability and integrability remain critical hurdles. Interdisciplinary collaboration is essential to accelerate advancements in quantum sensing technology, offering innovative pathways for the development of miniaturized, multifunctional integrated quantum sensors. By addressing these challenges, QPCs could revolutionize fields ranging from nanotechnology to quantum information science, enabling unprecedented levels of precision and functionality in next-generation devices.
Hu et al. (Thu,) studied this question.