Color center is a promising platform for quantum technologies, but their application is hindered by the typically random defect distribution and complex mesoscopic environment. Employing cathodoluminescence, we demonstrate that an ultraviolet-emitting single photon emitter can be readily activated and controlled on-demand at the twisted interface of two hexagonal boron nitride flakes. The brightness of the color center can be enhanced by two orders of magnitude by altering the twist angle. Additionally, a brightness modulation of nearly 100% of this color center is achieved by an external voltage. Our ab-initio GW calculations suggest that the emission is correlated to nitrogen vacancies and that a twist-induced moir\'e potential facilitates electron-hole recombination. This mechanism is further exploited to draw nanoscale color center patterns using electron beams.
@article{arxiv.2108.04747,
title = {Tuning color centers at a twisted interface},
author = {Cong Su and Fang Zhang and Salman Kahn and Brian Shevitski and Jingwei Jiang and Chunhui Dai and Alex Ungar and Ji-Hoon Park and Kenji Watanabe and Takashi Taniguchi and Jing Kong and Zikang Tang and Wenqing Zhang and Feng Wang and Michael Crommie and Steven G. Louie and Shaul Aloni and Alex Zettl},
journal= {arXiv preprint arXiv:2108.04747},
year = {2021}
}