Modulation of electronic structure properties in bilayer phosphorene nanoribbons by transition metal atoms

Abstract

To explore the novel properties and applications of two-dimensional black phosphorene, we perform a first-principles study on the modulation of the structure and electronic properties of bilayer phosphorene nanoribbons (BPNRs) by using transition metal (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) atoms. For one-dimensional zigzag-edge AA-stacked bilayer phosphorene nanoribbons with hydrogen passivation, we find that the atomic stacking of the BPNRs reorders from the AA to the AE stacking. The AE-stacked structure is the most stable structure for one-dimensional zigzag BPNRs. All the BPNRs with widths N = 4–10 exhibit semiconductor character with indirect band gaps (1.17, 1.01, 0.92, 0.84, 0.75, 0.74, and 0.72 eV), which gradually decrease with increasing nanoribbon width. The adsorption energies show that all the TM atom-adsorbed 4-BPNR compound systems [PTMP] can form stable structures, however, the most stable structures have different adsorption energies (−9.38, −10.73, −13.19, −8.26, −13.68, −9.73, −10.41, −10.33, and −5.98 eV) for different TM (Sc, Ti, V, Cr, Mn, Fe, Co, Ni and Cu) atoms. The calculated bond lengths, charge transfer, and difference charge density of [PMnP] systems indicate that there are strong chemical interactions between the TM atoms and their adjacent P atoms in the BPNRs, resulting in the formation of TM-P ionic bonds. The adsorption of TM atoms induces various electronic structures in 4-BPNR. The [PTMP]1 systems exhibit metallic properties with the adsorption of Sc, Co, and Cu atoms, and semiconductor properties with the adsorption of Ti, V, Cr, Mn, Fe, and Ni atoms with band gaps of 0.30, 0.18, 0.19, 0.20, 0.61, and 0.08 eV, respectively. The Ni and Cu adsorption systems show magnetic quenching with no magnetic moments in all the compound systems [PTMP]. The [PCrP]1 has the maximum magnetic moment of approximately 3.62 μB amongst all the [PTMP]1 systems, while the [PVP]1 and [PMnP]1 systems have magnetic moments of 1.66 μB and 1.84 μB, respectively. Our results show that TM atom-adsorbed bilayer phosphorene nanoribbons exhibit tunable electronic structures and magnetic properties for potential applications in nanoelectronics.