形变小直径扶手椅型碳纳米管的电子性质

Electron properties of deformed armchair single-walled carbon nanotubes with small diameter

在紧束缚近似下,解析地推导了轴向拉伸和扭转形变下小直径单壁碳纳米管(SWNT)的能量色散关系.分析了拉伸和扭转形变对小直径扶手椅型SWNT的电子性质的影响.结果表明,在拉伸形变下扶手椅型SWNT仍然是导体,但其费米速度随拉伸比的变大而变大;在拉伸比不变的情况下,考虑曲率效应后其费米速度变大.在扭转形变下,扶手椅型SWNT变成了半导体,其能隙随扭转度的变大而变大;在扭转度不变的情况下,考虑曲率效应后能隙变化不大.

By tight-binding approximation, the energy dispersion of small diameter single-walled carbon nanotubes （SWNT） under tensile and torsional strains has been derived. The effect of tensile and torsional strains on electronic properties of small diameter armchair SWNT has been discussed. It was found that, under tensile strain, the armchair SWNT still was metallic, but the Fermi velocities of them increased with increasing tensile strain. Considering the curvature effect, the Fermi velocity was larger than that of without curvature effect at the fixing tensile strains. Under torsional strains, the armchair SWNT was semiconductors. The energy gap increased with increasing torsional strains, while the energy gap of the armchair SWNT was not change greatly with and without the curvature effect at the fixing torsional strains.