Related papers: Unresolved problems in superconductivity of CaC6
Recently deiscovered superconductivity in YbC$_6$ and CaC$_6$ at temperatures substantially higher than previously known for intercalated graphites, raised several new questions: (1) Is the mechanism considerably different from the…
The superconducting state of Ca-intercalated graphite CaC6 has been investigated by specific heat measurements. The characteristic anomaly at the superconducting transition (Tc = 11.4 K) indicates clearly the bulk nature of the…
The out-of-plane intercalate phonons of superconducting YbC6 have been measured with inelastic x-ray scattering. Model fits to this data, and previously measured out-of-plane intercalate phonons in graphite intercalation compounds (GICs),…
On the basis of the model that was successfully applied to KC8, RbC8, and CsC8 in 1982, we have calculated the superconducting transition temperature Tc for CaC6 and YbC6 to find that the same model reproduces the observed Tc in those…
Using density functional theory we demonstrate that superconductivity in C6Ca is due to a phonon-mediated mechanism with electron-phonon coupling 0.83 and phonon-frequency logarithmic-average 24.7 meV. The calculated isotope exponents are…
The low energy phonons of two different graphite intercalation compounds (GICs) have been measured as a function of temperature using inelastic x-ray scattering (IXS). In the case of the non-superconductor BaC6, the phonons observed are…
We report the discovery of superconductivity below 1.65(6) K in Sr-intercalated graphite SrC6, by susceptibility and specific heat (Cp) measurements. In comparison with CaC6, we found that the anisotropy of the upper critical fields for…
Superconductivity in graphite intercalated compounds has been studied for more than 40 years and it is still not fully understood, despite the recent progress and the discovery of relatively high Tc superconductivity in CaC6 and YbC6.…
We present the results of a neutron scattering study of the high energy phonons in the superconducting graphite intercalation compound CaC$_6$. The study was designed to address hitherto unexplored aspects of the lattice dynamics in…
The pressure effect on the superconducting transition temperature ($T_c$) of the newly-discovered Ca-intercalated graphite compound CaC$_6$ has been investigated up to $\sim$ 16 kbar. $T_c$ is found to increase under pressure with a large…
In this letter we report the discovery of superconductivity in the isostructural graphite intercalation compounds C6Yb and C6Ca, with transition temperatures of 6.5K and 11.5K respectively. A structural characterisation of these compounds…
The field of superconductivity in the class of materials known as graphite intercalation compounds has a history dating back to the 1960s. This paper recontextualizes the field in light of the discovery of superconductivity in CaC6 and YbC6…
Superconductivity in intercalated graphite CaC6 and H under extreme pressure, in the framework of superconducting density functional theory, is discussed. A detailed analysis on how the electron-phonon and electron-electron interactions…
Using the {\it ab initio} anisotropic Eliashberg theory including Coulomb interactions, we investigate the electron-phonon interaction and the pairing mechanism in the recently-reported superconducting Ca-intercalated bilayer graphene. We…
We present first-principles calculations on systems consisting of a few layers of graphene and lithium. In particular, we investigate the evolution of the electron-phonon coupling strength with increasing number of layers. We find that, for…
Using density functional theory we investigate the occurrence of superconductivity in AC$_6$ with A=Mg,Ca,Sr,Ba. We predict that at zero pressure, Ba and Sr should be superconducting with critical temperatures (T$_c$) 0.2 K and 3.0 K,…
We investigate the dispersion and temperature dependence of a number of phonons in the recently discovered superconductor CaC6 utilizing inelastic x-ray scattering. Four [00L] and two ab-plane phonon modes are observed, and measured at…
We have measured the Ca isotope effect in the newly discovered superconductor CaC6. The isotope effect coefficient is 0.50(7). If one assumes that this material is a conventional electron-phonon coupled superconductor, this result shows…
In this letter, we report the discovery of superconductivity in Li3Ca2C6. Several graphite intercalation compounds (GICs) with electron donors, are well known as superconductors. It is probably not astonishing, since it is generally…
Recent observation of proximity effect \cite{Morpurgo:2007} has ignited interest in superconductivity in graphene and its derivatives. We consider Ca-intercalated graphene bilayer and argue that it is a superconductor, and likely with a…