Superconductivity in Ca-doped graphene laminates.
Superconductivity in Ca-doped graphene laminates.
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DOI：
10.1038/srep23254
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发表时间：
2016-03-16
影响因子：
4.6
通讯作者：
Nair RR
中科院分区：
文献类型：
--
作者：
Chapman J;Su Y;Howard CA;Kundys D;Grigorenko AN;Guinea F;Geim AK;Grigorieva IV;Nair RR
尽管石墨烯有一长串特殊的电子特性和许多关于石墨烯超导性可能性的理论预测，但它的直接和明确的实验观察尚未实现。我们在弱相互作用、金属修饰的石墨烯晶体中寻找超导性，这些石墨烯晶体组装成所谓的石墨烯层压板，由分离良好且电子解耦的石墨烯微晶组成。我们报告了所有Ca掺杂石墨烯层压板的强大超导性。它们在104至106 K之间的温度（Tc）下变得超导，其中Tc强烈依赖于Ca层的限制和石墨烯中的感应电荷载流子浓度。我们发现，钙是唯一的掺杂剂，诱导在石墨烯层压板中的超导性高于1.8 K在我们的实验中使用的几种掺杂剂，如钾，铯和锂。通过揭示通过掺杂和限制金属层的超导响应的可调谐性，我们的工作表明，在独立的，金属装饰的单层石墨烯中实现超导性是以金属层的最佳限制和足够的掺杂为条件的，从而使其实验实现在掌握之中。
Despite graphene’s long list of exceptional electronic properties and many theoretical predictions regarding the possibility of superconductivity in graphene, its direct and unambiguous experimental observation has not been achieved. We searched for superconductivity in weakly interacting, metal decorated graphene crystals assembled into so-called graphene laminates, consisting of well separated and electronically decoupled graphene crystallites. We report robust superconductivity in all Ca-doped graphene laminates. They become superconducting at temperatures (Tc) between ≈4 and ≈6 K, with Tc’s strongly dependent on the confinement of the Ca layer and the induced charge carrier concentration in graphene. We find that Ca is the only dopant that induces superconductivity in graphene laminates above 1.8 K among several dopants used in our experiments, such as potassium, caesium and lithium. By revealing the tunability of the superconducting response through doping and confinement of the metal layer, our work shows that achieving superconductivity in free-standing, metal decorated monolayer graphene is conditional on an optimum confinement of the metal layer and sufficient doping, thereby bringing its experimental realization within grasp.