摘要
基于密度泛函理论和广义梯度近似的第一原理方法,系统研究了应变对一维carbyne(卡拜)链原子键性质的调控机理.结果表明,轴向压缩应变的增加将导致carbyne链中碳-碳单键和碳-碳三键之间的键长差值越来越小,最终变为零.通过分析能带结构和差分电荷密度,发现当压缩应变为16%时,carbyne链由半导体转变为金属.当应变为17%时,声子谱出现虚频.在可研究范围内,应变对carbyne链的热容量有增强作用.而且,carbyne链的刚度远大于石墨烯和碳纳米管.
One-dimensional(1D)carbyne chain has the potential applications in the nanoelectronic devices due to its unique properties.Although some progress of the mechanical and thermal properties of 1D carbyne chain has been made,the physical mechanism of the strain modulation of atomic bond nature remains unclear.In order to explore the strain effects on the mechanical and related physical properties of 1D carbyne chain,we systematically investigate the strain-dependent bond nature of 1D carbyne chain based on the first-principles calculations of density functional theory and generalized gradient approximation.It is found that when the compressive strain is 16%,the bonding nature of 1D carbyne chain is changed,and the bond length alternation of single and triple bonds in 1D carbyne chain tends to zero,which originates from the difference in bond strength between single bond and triple bond.Moreover,1D carbyne chain can change from semiconductor into metal when the compressive strain is 16%indicated by analyzing the band structure and related differential charge density.When the strain is 17%,the phonon spectrum has an imaginary frequency.Besides,when the ambient temperature is less than 510 K,the heat capacity of 1D carbyne chain decreases with strain increasing.However,more phonon modes will be activated at larger strains when the temperature is higher than 510 K,and the heat capacity is enhanced gradually with strain increasing.Also,the stiffness coefficient of 1D carbyne chain is larger than that of graphene and carbon nanotube.These results conduce to the fundamental understanding of atomic bond nature in 1D carbyne chain under different strains.
作者
侯璐
童鑫
欧阳钢
Hou Lu;Tong Xin;Ouyang Gang(Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education,Key Laboratory for Matter Microstructure and Function of Hunan Province,School of Physics and Electronics,Hunan Normal University,Changsha 410006,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2020年第24期237-243,共7页
Acta Physica Sinica
基金
国家自然科学基金(批准号:11574080,91833302)资助的课题.
关键词
carbyne链
第一性原理
电子结构
热容
carbyne
first-principles calculations
electronic structure
heat capacity
