Noble metal dopants modified two-dimensional zinc oxide: Electronic structures and magnetic properties

Abstract

Two-dimensional materials have attracted great attentions due to their novel properties and promising applications in opto-electronic and spintronics devices, but the advance on engineering suitable band gap and ferromagnetic behaviour is still undergoing. Here, the electronic structures and magnetic properties of NM-doped (NM=Pd, Pt, Ag, Au, Cu) ZnO monolayer are investigated using first-principles calculations. The results show that the formation of NM-doped ZnO monolayer is easier under the O-rich condition than under the Zn-rich condition. Furthermore, the band gap of the ZnO monolayer becomes narrowed after NM doping. Moreover, all NM-dopants induce the polarization of the ZnO monolayer, and the total magnetic moments are within 0.8–2.0 μB. The origin is attributed to the spin states of NM-dxy, NM-dx2-y2 and py, px of their neighboring O atoms. In addition, we found that the Ag-, Au-, and Cu-doped ZnO monolayers are ferromagnetic half-metals, while Pd- and Pt-doping cases are ferromagnetic semiconductors. The present results demonstrate that NM-doping is a proper way to tailor the electronic and magnetic properties of the ZnO monolayer so as to expand its utilization in nanoelectronics and spintronics.