The transmission properties for square potential barriers have been investigated and compared from graphene to a dice lattice via a variable coupling parameter. There are two limiting cases of pseudospin 1/2 and 1, respectively. The perfect Klein tunneling has been obtained for all parameter conditions. With the increase of the coupling parameter, the tunneling probability increases at oblique incidence. The tunneling shows little dependence on the number of barriers for the dice model. However, the barrier number is an effective factor to tune the transmission feature in graphene. The tunneling peaks can be analyzed from the energy band structure in the expanded periodic potential system and the wave function distribution in the well/barrier regions. The present findings are useful in the development of electronic devices based on quantum transport property with massless pseudospin particles.
Adsorption and dissociation of O 2 molecule on the MoSe 2 and MoTe 2 monolayers are studied by using density functional theory (DFT) within the generalized gradient approximation (GGA) and a supercell approach. The physisorbed O 2 molecule on MoSe 2 and MoTe 2 with a magnetic moment (MM) close to that for an isolated O 2 molecule has small adsorption energy and long distance from the surface. The dissociative adsorption of configuration R5(R6) is the most stable adsorption site, whereas the chemisorption of O 2 is unfavorable at all adsorption sites. The dissociative adsorption of configuration R4 induces dramatic changes of electronic structures and localized spin polarization both for monolayer MoSe 2 and MoTe 2 . The analysis of electronic density of states (DOSs) shows that the contribution of spin polarization is mainly from the hybridization between O-p, Se(Te)-p and Mo-d orbitals.
We have investigated the electronic and magnetic properties of electron-doped Sr 2−x LaxFeReO 6 (x = 0.0, 0.25, 0.5) using first-principles density functional theory within the generalized gradient approximation (GGA) and GGA + U schemes. Our results reveal that the symmetry of the La-doped compounds is decreased from tetragonal I4/m for perfect sample to monoclinic P 2 1 /n. With increasing La content the absolute magnetic moment of the Re site increases distinctly and the doped electrons are considered to occupy mainly the down-spin Re 5d band from the band calculation. Electronic doping is found to enhance the Curie temperature (Tc) and stabilize the ferromagnetic half-metallic ground states of Sr 2 FeReO 6 . And it is found that the increase of Tc is mainly caused by the increase of ferromagnetic interaction between the Fe-O-Fe.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.