Lateral Composite Structures of Graphene/Graphane/Graphone: Electronic Confinement, Heterostructures with Tunable Band Alignment, and Magnetic State

Graphene can be hydrogenated fully on both sides andalso semihydrogenatedon one side to constitute graphane and graphone, respectively. Whileboth are wide band gap semiconductors, graphone also acquires a magneticground state originating from unpaired & pi;-bonds. We predict thatlateral composite structures/heterostructures can be constructed bythe patterned dehydrogenation of graphane or graphone with commensurateinterfaces, which display diverse physical properties depending ontheir constituents, interface geometry, and size. When constructedby consecutive graphane and graphene strips of very narrow width,they can attain exclusive electronic and magnetic properties in 2D,which are different from those of both parent materials. However,periodic and commensurate semiconductor-semiconductor heterostructureswith straddling band alignment and tunable band gaps can form, ifthe widths of strips with the armchair interface are wide enough toentail confinements of electronic states and hence to change the dimensionalityof the system from 2D to 1D. Depending on the type of zigzag interface,periodic heterostructures attain spin polarized straddling band alignments.Composite structures patterned on graphone can form magnetic semiconductor-semiconductorheterostructures, which have different staggered band alignments fordifferent spin polarization. Specifically, under the in-plane electricfield, a single heterostructure constructed on zigzag nanoribbonscan change its magnetic state and start to operate as a magnetic diodefor one spin direction. All of these composite structures, which allowelectronic confinement followed by a change of dimensionality, offervarious quantum structures and functionalities with potential applicationsin spintronics.