The ultrathin film limit has been shown to be a rich playground for unusual low dimensional physics. Taking the example of SrRuO3 which is ferromagnetic and metallic at the bulk limit, one finds that it becomes antiferromagnetic and insulating at the three monolayers limit when grown on SrTiO3. The origin of the insulating state is traced to strongly orbital dependent exchange splittings. A modest compressive strain of 1% of the SrTiO3 substrate is then found to drive the system into a highly confined two-dimensional 100% spin polarized metallic state. This metal-insulator transition driven by a modest strain could be useful in two state device applications.
The electronic structure of Mn doped GaAs and GaN have been examined within a multiband Hubbard model. By virtue of the positioning of the Mn d states, Mn doped GaAs is found to belong to the p-d metal regime of the Zaanen-Sawatzky-Allen phase diagram and its variants while Mn doping in GaN belongs to the covalent insulator regime. Their location in the phase diagram also determines how they would behave under quantum confinement which would increase the charge transfer energy. The ferromagnetic stability of Mn doped GaAs, we find, increases with confinement therefore providing a route to higher ferromagnetic transition temperatures.
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.