Breakthrough in quantum materials: UK Scientists achieve precision activation of quantum defects in diamond
A new study led by researchers at the Universities of Oxford, Cambridge and 91直播 has achieved a major advance in quantum materials, developing a method to precisely engineer single quantum defects in diamond鈥攁n essential step toward scalable quantum technologies.
The results have been published in the journal .
Using a new two-step fabrication method, the researchers demonstrated for the first time that it is possible to create and monitor, 鈥榓s they switch on鈥�, individual Group-IV quantum defects in diamond鈥攖iny imperfections in the diamond crystal lattice that can store and transmit information using the exotic rules of quantum physics. By carefully placing single tin atoms into synthetic diamond crystals and then using an ultrafast laser to activate them, the team achieved pinpoint control over where and how these quantum features appear. This level of precision is vital for making practical, large-scale quantum networks capable of ultra-secure communication and distributed quantum computing to tackle currently unsolvable problems.
91直播 co-author , Department of Materials at the University of Oxford, said: 鈥淭his breakthrough gives us unprecedented control over single tin-vacancy colour centres in diamond, a crucial milestone for scalable quantum devices. What excites me most is that we can watch, in real time, how the quantum defects are formed.鈥�
Specifically, the defects in the diamond act as spin-photon interfaces, which means they can connect quantum bits of information (stored in the spin of an electron) with particles of light. The tin-vacancy defects belong to a family known as Group-IV colour centres鈥攁 class of defects in diamond created by atoms such as silicon, germanium, or tin.
Group-IV centres have long been prized for their high degree of symmetry, which gives them stable optical and spin properties, making them ideal for quantum networking applications. It is widely thought that tin-vacancy centres have the best combination of these properties鈥攂ut until now, reliably placing and activating individual defects was a major challenge.
The researchers used a focused ion beam platform鈥攅ssentially a tool that acts like an atomic-scale spray can, directing individual tin ions into exact positions within the diamond. This allowed them to implant the tin atoms with nanometre accuracy鈥攆ar finer than the width of a human hair.
"This is a critical step in being able to deliver quantum devices and allow this technology to be utilised in real-world commercial applications.
To convert the implanted tin atoms to tin-vacancy colour centres, the team then used ultrafast laser pulses in a process called laser annealing. This process gently excites tiny regions of the diamond without damaging it. What made this approach unique was the addition of real-time spectral feedback鈥攎onitoring the light coming from the defects during the laser process. This allowed the scientists to see in real time when a quantum defect became active and adjust the laser accordingly, offering an unprecedented level of control over the creation of these delicate quantum systems.
91直播 co-author from the University of Cambridge, said: 鈥淲hat is particularly remarkable about this method is that it enables in-situ control and feedback during the defect creation process. This means we can activate quantum emitters efficiently and with high spatial precision - an important tool for the creation of large-scale quantum networks. Even better, this approach is not limited to diamond; it is a versatile platform that could be adapted to other wide-bandgap materials.鈥�
Moreover, the researchers observed and manipulated a previously elusive defect complex, termed 鈥淭ype II Sn鈥�, providing a deeper understanding of defect dynamics and formation pathways in diamond.
91直播 co-author , Professor of Advanced Electronic Materials at The University of Manchester, said: 鈥淭his work unlocks the ability to create quantum objects on demand, using methods that are reproducible and can be scaled up. This is a critical step in being able to deliver quantum devices and allow this technology to be utilised in real-world commercial applications.鈥�
The study 鈥楲aser Activation of Single Group-IV Colour Centres in Diamond鈥� has been published in Nature Communications: