Fang Hanyan, Gallardo Aurelio, Dulal Dikshant, Qiu Zhizhan, Su Jie, Telychko Mykola, Mahalingam Harshitra, Lyu Pin, Han Yixuan, Zheng Yi, Cai Yongqing, Rodin Aleksandr, Jelínek Pavel, Lu Jiong
Department of Chemistry, National University of Singapore, Singapore 117543, Singapore.
Institute of Physics, Academy of Sciences of the Czech Republic, Prague 162 00, Czech Republic.
Phys Rev Lett. 2022 Apr 29;128(17):176801. doi: 10.1103/PhysRevLett.128.176801.
We report that monoelemental black phosphorus presents a new electronic self-passivation scheme of single vacancy (SV). By means of low-temperature scanning tunneling microscopy and noncontact atomic force microscopy, we demonstrate that the local reconstruction and ionization of SV into negatively charged SV^{-} leads to the passivation of dangling bonds and, thus, the quenching of in-gap states, which can be achieved by mild thermal annealing or STM tip manipulation. SV exhibits a strong and symmetric Friedel oscillation (FO) pattern, while SV^{-} shows an asymmetric FO pattern with local perturbation amplitude reduced by one order of magnitude and a faster decay rate. The enhanced passivation by forming SV^{-} can be attributed to its weak dipolelike perturbation, consistent with density-functional theory numerical calculations. Therefore, self-passivated SV^{-} is electrically benign and acts as a much weaker scattering center, which may hold the key to further enhance the charge mobility of black phosphorus and its analogs.
我们报道了单元素黑磷呈现出一种新的单空位（SV）电子自钝化机制。通过低温扫描隧道显微镜和非接触原子力显微镜，我们证明了SV的局部重构以及其电离为带负电的SV⁻会导致悬键的钝化，进而使带隙态猝灭，这可以通过温和的热退火或扫描隧道显微镜针尖操纵来实现。SV呈现出强烈且对称的弗里德尔振荡（FO）图案，而SV⁻则显示出不对称的FO图案，其局部扰动幅度降低了一个数量级且衰减速率更快。通过形成SV⁻实现的增强钝化可归因于其类似偶极子的微弱扰动，这与密度泛函理论数值计算结果一致。因此，自钝化的SV⁻在电学上是良性的，并且作为一个弱得多的散射中心，这可能是进一步提高黑磷及其类似物电荷迁移率的关键。
