Nguyen Khoi T, Gaur Anshu, Shim Moonsub
Department of Materials Science and Engineering and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Phys Rev Lett. 2007 Apr 6;98(14):145504. doi: 10.1103/PhysRevLett.98.145504.
Evolution of G-band modes of single metallic carbon nanotubes with the Fermi level shift is examined by simultaneous Raman and electron transport studies. Narrow Lorentzian line shape and upshifted frequencies are observed near the van Hove singularities. However, all G modes soften and broaden at the band crossing point. The concurrent appearance of an asymmetric Fano line shape at this point indicates that phonon-continuum coupling is intrinsic to single metallic tubes. The apparent Lorentzian line shapes of as-synthesized metallic tubes are induced by O2 adsorption causing the Fermi level shift.
通过同步拉曼和电子输运研究，考察了单金属碳纳米管的G带模式随费米能级移动的演变。在范霍夫奇点附近观察到窄的洛伦兹线形和频率上移。然而，所有G模式在能带交叉点处都会软化和展宽。此时不对称的法诺线形同时出现，表明声子 - 连续体耦合是单金属管固有的。合成态金属管明显的洛伦兹线形是由O2吸附导致费米能级移动引起的。
