Monolayer α-graphyneisanewtwo-dimensionalcarbonallotropewithmanyspecialfeatures.Inthis worktheelectronicpropertiesofAA-andAB stackedbilayersofthismaterialandthentheoptical properties arestudied,using first principleplanewavemethod.TheelectronicspectrumhastwoDirac cones forAAstackedbilayer α-graphyne.ForAB-stackedbilayer,theinterlayerinteractionchangesthe linear bandsintoparabolicbands.TheopticalspectraofthemoststableAB stackedbilayercloselyre- semble tothatofthemonolayer,exceptforsmallshiftsofpeakpositionsandincreasingoftheirintensity. For AB-stackedbilayer,apronouncedpeakhasbeenfoundatlowenergiesundertheperpendicular polarization. ThispeakcanbeclearlyascribedtothetransitionsattheDiracpointasaresultofthesmall degeneracyliftinthebandstructure.
