The structural and electronic properties of monovacancy,divacancy defects within crystalline silicon have been investigated systematically using a new tight-binding model with a 216-atom supercell.The formation energi...The structural and electronic properties of monovacancy,divacancy defects within crystalline silicon have been investigated systematically using a new tight-binding model with a 216-atom supercell.The formation energies and energy levels of all the defect configurations are carefully calculated.The results show that atoms nearer to the defects naturally contribute to gap states more,and are comparable with the experimental values.展开更多
Using first-principles calculations,we investigate the structural,electronic and hydrogenated properties of the hexagonal BC_(7) sheet.The computed energy bands and density of states indicate that the BC_(7) sheet is ...Using first-principles calculations,we investigate the structural,electronic and hydrogenated properties of the hexagonal BC_(7) sheet.The computed energy bands and density of states indicate that the BC_(7) sheet is a metal,and its metallicity mainly originates from the non-bonding pz electrons of the diagonal carbon of the B atom.When these carbon atoms are fully passivated by H atoms,the BC_(7) sheet becomes a semiconductor with a band gap of 2.41 eV.Our studies demonstrate that changing both the proportion of the boron atoms in the boron carbon sheet and its hydrogenation can tune the electronic properties of boron carbon two-dimensional material.展开更多
Carbon nanotubes with finite lengths should be natural components of future“nano devices”.Based on orthogonal tight-binding molecular dynamics simulations,we report our study of formation energies,optimal geometrica...Carbon nanotubes with finite lengths should be natural components of future“nano devices”.Based on orthogonal tight-binding molecular dynamics simulations,we report our study of formation energies,optimal geometrical structures and active sites of carbon nanotubes with finite lengths.This should be useful to understand the properties of such natural components.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.69876035,the Fund of Chinese Academy of Sciences and the Fund of University of Science and Technology of China.
文摘The structural and electronic properties of monovacancy,divacancy defects within crystalline silicon have been investigated systematically using a new tight-binding model with a 216-atom supercell.The formation energies and energy levels of all the defect configurations are carefully calculated.The results show that atoms nearer to the defects naturally contribute to gap states more,and are comparable with the experimental values.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10964012,10904054,11064004,11264014 and 11234013the Natural Science Foundation of Jiangxi under Grant Nos 2009GQW008 and 2010GZW0028the Cultivating Youths of Outstanding Ability in Jiangxi Normal University,the‘Gan-po talent 555’Project of Jiangxi Province and the Oversea Returned Project from the Ministry of Education.
文摘Using first-principles calculations,we investigate the structural,electronic and hydrogenated properties of the hexagonal BC_(7) sheet.The computed energy bands and density of states indicate that the BC_(7) sheet is a metal,and its metallicity mainly originates from the non-bonding pz electrons of the diagonal carbon of the B atom.When these carbon atoms are fully passivated by H atoms,the BC_(7) sheet becomes a semiconductor with a band gap of 2.41 eV.Our studies demonstrate that changing both the proportion of the boron atoms in the boron carbon sheet and its hydrogenation can tune the electronic properties of boron carbon two-dimensional material.
基金Supported in part by Ministry of Education,PRC,the National PAN-DENG Project(95-YU-41)the National Natural Science Foundation of China under Grant No.69876035National High-Tech ICF Committee in China.
文摘Carbon nanotubes with finite lengths should be natural components of future“nano devices”.Based on orthogonal tight-binding molecular dynamics simulations,we report our study of formation energies,optimal geometrical structures and active sites of carbon nanotubes with finite lengths.This should be useful to understand the properties of such natural components.
