arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1005.5089cond-mat.str-el
收藏

石墨烯导电性缺口的特征

Signatures of a gap in the conductivity of graphene

Joaquín E. Drut, Timo A. Lähde, Eero Tölö

摘要:

最近首次测量了悬浮石墨烯的电导率,发现在大载流子密度下表现为σ~ \sqrt{|n|},这与Dirac准粒子的预期一致。悬浮样品的电荷不均匀性大大降低,这揭示了σ(T)的意想不到的绝缘趋势。高于过渡密度n*,温度依赖性被发现恢复到金属。我们表明,这些功能的直流电导率是一致的一个简单的模型的间隙狄拉克准粒子,在附近的电荷中性点的间隙的具体签名。我们的研究结果是让人想起在半导体材料的电导率分布,表现出热激活T \geq \tilde T和T \leq \tilde T,其中\tilde T是由饱和密度\tilde n与剩余电荷的不均匀性的弱T依赖的背景。我们讨论了石墨烯带隙的可能起源以及替代方案。

英文摘要:

The electrical conductivity of suspended graphene has recently been measured for the first time, and found to behave as σ~ \sqrt{|n|} as expected for Dirac quasiparticles at large carrier density. The charge inhomogeneity is strongly reduced in suspended samples, which revealed an unexpected insulating trend in σ(T). Above a transitional density n*, the temperature dependence was found to revert to metallic. We show that these features of the DC conductivity are consistent with a simple model of gapped Dirac quasiparticles, with specific signatures of a gap in the vicinity of the charge-neutrality point. Our findings are reminiscent of the conductivity profile in semiconducting materials, exhibiting a thermal activation for T \geq \tilde T and a weakly T-dependent background for T \leq \tilde T, where \tilde T is given by the saturation density \tilde n associated with the residual charge inhomogeneity. We discuss possible origins of a bandgap in graphene as well as alternative scenarios.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑