Abnormal behavior of potassium adsorbed phosphorene

摘要

First-principles calculation is carried out to study adsorption of potassium (K) on phosphorene, a single layer of black phosphorus (BP). Interesting adsorption distance dependent electronic properties were found for the K adsorption on phosphorene surface, which is different from that for the K adsorption on a few-layer black phosphorus. While the bandgap of few-layer BP decreases monotonically as K approaches its surface and a Dirac point emerges, that of phosphorene decreases first and then increases, remaining open at any separation between K and phosphorene. This abnormal behavior is a result of weaker Stark effect and charge localization in phosphorene.