Research On The Design And Performance Of A New Type Of Carbon Allotrope Based On First-principles Methods

Carbon is an element widely existing in nature,and its allotrope has a pivotal position in the material system.Carbon allotropes exist widely in nature in different forms and different dimensions.The carbon allotrope has various structural forms and different uses in practical applications,but each has its own advantages,making people full of expectations for more excellent carbon allotrope.Nowadays,many achievements have been made in the electronic structure and mechanics of carbon materials,but the exploration of new carbon materials and the continuous search for more excellent materials continue.This thesis uses the basic theory and method of theoretical calculation to design three new carbon allotropes of TR-C3 carbon,MN carbon and SW carbon,and calculates the crystal structure,electronic structure and the nature of mechanics.The three carbon allotropes exhibit different electrical and mechanical properties.Among them,SW carbon exhibits semiconductor properties with a band gap of 1.930 eV,and its variants exhibit metallic properties.The tensile strength in the [100] crystal direction reaches a maximum of about 82.4GPa,and the hardness reaches about 89 GPa.The second carbon allotrope is named MN carbon,which exhibits semiconductor properties.The band gap is 1.875 eV,the hardness reaches 85.4GPa,and the tensile strength along the [001] crystal is 76 GPa,which has good mechanical properties.The third TR-C3 carbon is a non-metallic carbon allotrope,the band gap width is 2.575 eV,the hardness value is 55.1GPa,and the [001] crystal tensile strength is 70.3GPa,which can be judged that TR-C3 carbon has excellent performance.This dissertation designs three new carbon allotropes of TR-C3 carbon,MN carbon,and SW carbon.First-principles research that comprehensively utilizes its electrical and mechanical properties will provide theories for the design of potential functional carbon crystal structures.The foundation provides theoretical guidance for experimentally testing and preparing new(functional)carbon crystal materials.