حسین شیرکانی

It is well known that future information technology relies upon electronic states other than charge, through the feasibility of constructingspintronicandvalleytronicdevices.Themainchallengeinsuch applications isthegenerationandcontrolofthecorrespondingstatecurrents.Thepresentpaperisthus concerned withcharge,spinandvalleycurrentswhichintrinsicallydevelopinarmchairsilicene nanoribbons (ASNs).InpursuingthisconsiderationthewellestablishedKuboformulaisemployed. TakingthesymmetriesoftheASNintoaccount,weanalyzethestructureoftotalHamiltonianand demonstratehowthematrixelementsalongwiththesummationsinvolvedinthesuitablyadopted Kuboformula,maybeanalyticallycalculated.Theresultsso-obtainedalongwiththecorresponding figures revealthatallthreecurrentsdevelopinastep-wisemanner.Theheights,indicatingajumpinthe current, andtheplateaus,indicatingaconstantcurrent,areshowntobetunablebyadjustingthewidth and/or thebuckledeffect.Moreover,wedemonstratethatforparticular(critical)widthsaninversionin band gapsmayoccur,givingrisetoquantumphasetransitions.Morepracticalresultofthispaper,aswe show,isthefactthattheASNcangeneratepurespin or valleycurrentunderspecific conditionsplaced on thewidth,buckledeffectandFermienergy.Thematerialpresentedinthispaperthusprovidesnovel means ofgenerationandcontrolofthecharge,spinandvalleycurrents.