Band-Gap-Dependent Electronic Compressibility of Carbon Nanotubes in the Wigner Crystal Regime
Band-Gap-Dependent Electronic Compressibility of Carbon Nanotubes in the Wigner Crystal Regime
复制标题
维格纳晶体体系中碳纳米管的带隙相关电子压缩性
DOI：
10.1103/physrevlett.123.197701
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发表时间：
2019
影响因子：
8.6
通讯作者：
Deshpande, Vikram V.
中科院分区：
文献类型：
--
作者：
Lotfizadeh, Neda;McCulley, Daniel R.;Senger, Mitchell J.;Fu, Han;Minot, Ethan D.;Skinner, Brian;Deshpande, Vikram V.
电子压缩性是基态能量相对于总电子数的二阶导数，是一个可测量的量，揭示了系统的相互作用强度，可用于表征电子的有序晶格（称为维格纳晶体）。在这里，我们测量了低密度维格纳晶态中单个悬浮超净碳纳米管的电子压缩率。使用低温量子输运测量，我们确定了具有不同带隙的纳米管中载流子数量的可压缩性。我们观察到压缩率与载流子数量之间的两种性质不同的趋势，这两种趋势都可以使用维格纳晶体的理论模型来解释，该模型解释了载流子所经历的带隙和限制电势。我们提取了单个纳米管的相互作用强度作为载流子数量的函数，并表明可压缩性可用于区分强相互作用状态和弱相互作用状态。
Electronic compressibility, the second derivative of ground-state energy with respect to total electron number, is a measurable quantity that reveals the interaction strength of a system and can be used to characterize the orderly crystalline lattice of electrons known as the Wigner crystal. Here, we measure the electronic compressibility of individual suspended ultraclean carbon nanotubes in the low-density Wigner crystal regime. Using low-temperature quantum transport measurements, we determine the compressibility as a function of carrier number in nanotubes with varying band gaps. We observe two qualitatively different trends in compressibility versus carrier number, both of which can be explained using a theoretical model of a Wigner crystal that accounts for both the band gap and the confining potential experienced by charge carriers. We extract the interaction strength as a function of carrier number for individual nanotubes and show that the compressibility can be used to distinguish between strongly and weakly interacting regimes.