Evidence for superconductivity in Li-decorated monolayer graphene
Evidence for superconductivity in Li-decorated monolayer graphene
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DOI：
10.1073/pnas.1510435112
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发表时间：
2015-09-22
影响因子：
11.1
通讯作者：
Damascelli, A.
中科院分区：
文献类型：
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作者：
Ludbrook, B. M.;Levy, G.;Damascelli, A.
单层石墨烯具有许多惊人的电子特性，超导性可以说是最显著的例外。理论上提出，可以通过用碱性吸附原子超晶格装饰石墨烯来增强电子-声子耦合来诱导超导性[Profeta G，Calandra M，Mauri F（2012）Nat Phys 8（2）：131-134]。虽然实验已经表明adatom诱导的电子-声子耦合的增强，超导性从未被观察到。使用角分辨光电子能谱（ARPES），我们表明，在低温下沉积在石墨烯上的锂强烈地改变了声子态密度，导致电子-声子耦合的增强高达λ类似或等于0.58。在石墨烯衍生的π * 带费米表面的一部分上，我们然后观察到类似于或等于0.9 meV的温度依赖性配对间隙的Delta的开口。据我们所知，这一结果第一次表明，Li修饰的单层石墨烯确实是超导的，T-c接近或等于5.9 K。
Monolayer graphene exhibitsmany spectacular electronic properties, with superconductivity being arguably the most notable exception. It was theoretically proposed that superconductivity might be induced by enhancing the electron-phonon coupling through the decoration of graphene with an alkali adatom superlattice [Profeta G, Calandra M, Mauri F (2012) Nat Phys 8(2): 131-134]. Although experiments have shown an adatom-induced enhancement of the electron-phonon coupling, superconductivity has never been observed. Using angle-resolved photoemission spectroscopy (ARPES), we show that lithium deposited on graphene at low temperature strongly modifies the phonon density of states, leading to an enhancement of the electron-phonon coupling of up to lambda similar or equal to 0.58. On part of the graphene-derived pi*-band Fermi surface, we then observe the opening of a Delta similar or equal to 0.9-meV temperature-dependent pairing gap. This result suggests for the first time, to our knowledge, that Li-decorated monolayer graphene is indeed superconducting, with T-c similar or equal to 5.9 K.