Direct observation of Born-Oppenheimer approximation breakdown in carbon nanotubes.
Direct observation of Born-Oppenheimer approximation breakdown in carbon nanotubes.
复制标题
直接观察碳纳米管中的玻恩-奥本海默近似击穿。
DOI：
10.1021/nl802854x
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发表时间：
2009
期刊：
影响因子：
10.8
通讯作者：
S. Cronin
中科院分区：
文献类型：
--
作者：
Adam W. Bushmaker;V. Deshpande;Scott S. Hsieh;M. Bockrath;S. Cronin
测量了单个、原始、悬浮、金属性单壁碳纳米管的拉曼光谱和电导。观察到G（-）带随着施加的小栅极电压而下移，最小值出现在E（F）= +/-（1）/（2）E（声子）处，与绝热预测相反。随后在较高的栅极电压的拉曼频率上移的结果在“W”形的拉曼位移曲线，同意以及与非绝热声子重整化模型。这一行为构成了理论预测的玻恩-奥本海默近似在单个单壁碳纳米管中的崩溃的第一个实验证实。
Raman spectra and electrical conductance of individual, pristine, suspended, metallic single-walled carbon nanotubes are measured under applied gate potentials. The G(-) band is observed to downshift with small applied gate voltages, with the minima occurring at E(F) = +/-(1)/(2)E(phonon), contrary to adiabatic predictions. A subsequent upshift in the Raman frequency at higher gate voltages results in a "W"-shaped Raman shift profile that agrees well with a nonadiabatic phonon renormalization model. This behavior constitutes the first experimental confirmation of the theoretically predicted breakdown of the Born-Oppenheimer approximation in individual single-walled carbon nanotubes.