Depth-dependent charge-state instability of nitrogen-vacancy centers in ion-implanted diamondRemoveChong Li, Yang Li, Mingchao Li, Doudou Zheng, Chenchen Tang, Jian Gao, Xin Li, Hao Guo, Zhonghao Li, Jun Tang, HuanFei Wen, Zongmin Ma, and Jun LiuPhys. Rev. B 114, 125306 (2026)