Possible room temperature superconductivity in conductors obtained by bringing alkanes into contact with a graphite surface

Abstract

In 1986, a cuprate superconductor (Ba-La-Cu-O system) having a critical temperature which goes over the BCS limit (~30 K) was discovered and then a cuprate superconductor (Y-Ba-Cu-O system) with a critical temperature higher than 77 K was discovered. Furthermore, a Hg-based cuprate with a critical temperature of 133 K was found. The 133 K is still the highest critical temperature of conventional superconductors under atmospheric pressure. We have shown that materials obtained by bringing n-alkanes into contact with graphite are capable of conducting electricity with almost no energy loss at room temperature. We here report that the sudden jump in resistance showing a phase transition is observed in the materials during heating by two-probe resistance measurement. The measured critical temperatures of the materials consisting of pitch-based graphite fibers and n-alkanes having 7-16 carbon atoms range from 363.08 to 504.24 K and the transition widths range between 0.15 and 3.01 K. We also demonstrate that superconductors with critical temperatures beyond 504 K are obtained by alkanes with 16 or more carbon atoms.

Identification of a possible superconducting transition above room temperature in natural graphite crystals

“…Figure 17 shows the remanence resistance ΔR(0) versus temperature for the HOPG flake. Note that the temperature dependence is similar to the other measured samples (see figures [14][15][16] but it has a larger scatter. This scatter is possibly due to the higher transition temperature, i.e.…”

“…Theoretical studies predict superconductivity at high temperatures in electronic systems with a flat band [6][7][8] as, for example, at the surface of rhombohedral graphite [9] or at the interfaces between this and Bernal graphite [10]. Whereas evidence for flat bands at the surface of epitaxial rhombohedral multilayer graphene was recently found [11], hints for the existence of superconductivity above room temperature in different graphite-based systems were reported in the last 40 years [12][13][14][15][16] without providing, however, any knowledge of the critical temperature T c .…”

High-temperature superconductors: underlying physics and applications

“…A novel type of superconducting phase has been reported by Kawashima where several forms of graphite and single-layer graphene wetted with alkanes exhibit superconductor-like properties above room temperature under ambient pressure [47]. The novelty is here that superconductivity is restricted to a certain temperature range below which it disappears.…”

Probable Cause for the Superconductor-Like Properties of Alkane-Wetted Graphite and Single-Layer Graphene above Room Temperature under Ambient Pressure

“…The "T c " of alkane-wetted pitch-based graphite fibers, defined as the temperature at which the resistance increases sharply on raising temperature, increases almost linearly from ~363 to ~504 K with increasing the molecular weight of the alkane from heptane to hexadecane. [13] This result means that the ZA mode of graphene is more effectively weakened with increasing the molecular weight of alkane, which in return indicates that the primary role of alkane-wetting is to weaken the ZA phonon mode of graphene. The above discussion suggests that other molecules in liquid state such as alkanols can also be used to wet graphene and make the FSNAP pairing mechanism operate above room temperature.…”