NMR evidence for gapped spin excitations in metallic carbon nanotubes.
NMR evidence for gapped spin excitations in metallic carbon nanotubes.
复制标题
金属碳纳米管中带隙自旋激发的核磁共振证据。
DOI：
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发表时间：
2005
影响因子：
8.6
通讯作者：
H. Kuzmany
中科院分区：
文献类型：
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作者：
P. Singer;P. Wzietek;H. Alloul;F. Simon;H. Kuzmany
利用13C核磁共振研究了双壁碳纳米管富集13C同位素内壁的自旋动力学。与预期相反，我们发现我们的数据集表明，对于大多数通过核磁共振检测到的内壁纳米管，自旋晶格弛豫时间（T1）具有相同的温度(T)和磁场(H)依赖性。在高温状态下（T约为>或= 150k），我们发现1/T1T对T和H的依赖关系与一维金属链一致。当T大约<或= 150k时，我们发现随着T的减小，1/T1T显著增加，然后在大约= 20k以下急剧下降。数据清楚地表明自旋激发谱中形成了一个间隙，其中间隙值2delta约= 40 K（等于3.7 meV）与H无关。
We report on the spin dynamics of 13C isotope enriched inner walls in double-wall carbon nanotubes using 13C nuclear magnetic resonance. Contrary to expectations, we find that our data set implies that the spin-lattice relaxation time (T1) has the same temperature (T) and magnetic field (H) dependence for most of the inner-wall nanotubes detected by NMR. In the high-temperature regime (T approximately > or = 150 K), we find that the T and H dependence of 1/T1T is consistent with a 1D metallic chain. For T approximately < or = 150 K we find a significant increase in 1/T1T with decreasing T, followed by a sharp drop below approximately = 20 K. The data clearly indicate the formation of a gap in the spin excitation spectrum, where the gap value 2delta approximately = 40 K (congruent to 3.7 meV) is H independent.