High-throughput screening of novel defects for quantum technologies

Point defects in semiconductors that can emit single photons and have controllable spin states are crucial for building quantum technologies such as secure communication networks and ultra-sensitive sensors. However, identifying the right defects is extremely challenging because of the vast number of possible configurations.

In a new study, researchers led by Abhishek K Singh, Professor in the Materials Research Centre, IISc, along with PhD students Shibu Meher and Manoj Dey, have developed a systematic high-throughput computational framework to address this challenge. Using advanced first-principles calculations, the team screened hundreds of charged point defects in 4H silicon carbide (4H-SiC), a material widely used in electronics, to find candidates suitable for quantum applications.

The framework successfully identified 13 quantum defects with desirable optical and spin properties. Among these, seven novel group-IV-related defects involving germanium (Ge), tin (Sn), and lead (Pb) were discovered. These defects can emit single photons in wavelength ranges relevant for telecommunication and mid-infrared applications, and exhibit strong optical transition dipole moments along with microwave-accessible spin splitting – key features for quantum control.

The approach was validated against known quantum defects, confirming its robustness and accuracy. This framework not only accelerates the discovery of optically active quantum defects but can also be adapted to other semiconductor hosts, paving the way for scalable quantum communication and sensing devices.

REFERENCE:
Meher S, Dey M, Singh A, High-throughput computational search for group-IV-related quantum defects as spin-photon interfaces in 4H-SiC, Physical Review B (2025).
https://doi.org/10.1103/lsxj-nvhw

LAB WEBSITE:
https://mrc.iisc.ac.in/abhishek-singh/