Search

In this paper, we have investigated the electronic structure and magnetic properties of K and Mn co-doped BaCd2As2 using density functional theory within the generalized gradient approximation (GGA) + U schemes. Calculations show that the ground state magnetic structure of Mn-doped BaCd2As2 is antiferromagnetic while K and Mn co-doped BaCd2As2 is ferromagnetic. Electronic structures indicate that the superexchange mechanism leads to the antiferromagnetic coupling between Mn atoms in Mn-doped BaCd2As2 while the hole-mediated Zener's p–d exchange mechanism leads to the ferromagnetic coupling between Mn atoms in K and Mn co-doped BaCd2As2. [ABSTRACT FROM AUTHOR]

In this paper, we have investigated the structural, electronic and magnetic properties of Ga12N12 cluster doped with monodoped and bidoped atoms within the density functional theory (DFT). Substitutional, exohedral and endohedral doping are considered. It is observed that both monodoped and bidoped clusters tend to be in exohedral doping. Mulliken population analysis is performed to obtain the charge transfer and magnetic moment. The magnetic moment is mainly derived from 3d orbitals of atom for all isomers, while the magnetic properties would rely on the Fe-Fe distance. [ABSTRACT FROM AUTHOR]

The electronic and optical properties of S- and/or Ce-(co)doped anatase titanium dioxide (TiO2) are investigated using density functional theory plus U (DFTU) calculations. The optimized total energy suggests that TiO2 codoping by Ce and S favours the configuration of one substitutional Ce atom occupied on a Ti site with one substitutional S atom either on its nearest neighboring O or Ti site. The calculated results show that all doping configurations exhibit remarkable red-shift and excellent photocatalytic properties compared with pure TiO2. These reinforced features can mainly be ascribed to the appearance of S states in the top of valence band (VB) and Ce states in the bottom of conduction band (CB) as well as the contribution from the increasing octahedral dipole moments. The synergetic effects of cationic Ce and anionic S can extend optical absorption edge, which results in higher absorption coefficient in the visible light region than that of the anionic S monodoping and cationic Ce monodoping case; in the same time, decreasing the codoping concentration leads to reduced optical absorption. Additionally, Ce and S as cations incorporating into TiO2 lattices can induce stronger redox potential with a lower defect formation energy under O-rich condition compared with other doping systems. [ABSTRACT FROM AUTHOR]

By adopting density functional theory in combination with nonequilibrium Green's functions, we investigated the electronic structure and transport properties of silicon/nitrogen (/) co-doping armchair graphene nanoribbons (AGNRs) with x co-dopant incorporated in neighboring carbon atoms. The results demonstrate that the electronic structure can be modulated by introducing x co-dopants in AGNRs. The striking negative differential resistance behaviors in the range of low bias can be observed in / co-doped AGNR devices. These remarkable properties suggest the potential application of / co-doping AGNRs in molectronics. [ABSTRACT FROM AUTHOR]