Einstein and Debye temperatures, electron-phonon coupling constant and a probable mechanism for ambient-pressure room-temperature superconductivity in intercalated graphite

2025/11/07 by E. F. Talantsev · 1 voice
Physics and Astronomy · #physics.gen-ph

paper · pdf · doi:10.1002/andp.202500546

Abstract

Recently, Ksenofontov et al (arXiv:2510.03256) observed ambient pressure room-temperature superconductivity in graphite intercalated with lithium-based alloys with transition temperature (according to magnetization measurements) T_c=330 K. Here, I analyzed the reported temperature dependent resistivity data ρ(T) in these graphite-intercalated samples and found that ρ(T) is well described by the model of two series resistors, where each resistor is described as either an Einstein conductor or a Bloch-Grüneisen conductor. Deduced Einstein and Debye temperatures are Θ_E,1 ≈ 250 K and Θ_E,2 ≈ 1,600 K, and Θ_D,1 ≈ 300 K and Θ_D,2 ≈ 2,200 K, respectively. Following the McMillan formalism, from the deduced Θ_E,2 and Θ_D,2, the electron-phonon coupling constant λ_e-ph = 2.2 - 2.6 was obtained. This value of λ_e-ph is approximately equal to the value of λ_e-ph in highly compressed superconducting hydrides. Based on this, I can propose that the observed room-temperature superconductivity in intercalated graphite is localized in nanoscale Sr-Ca-Li metallic flakes/particles, which adopt the phonon spectrum from the surrounding bulk graphite matrix, and as a result, conventional electron-phonon superconductivity arises in these nano-flakes/particles at room temperature. Experimental data reported by Ksenofontov et al (arXiv:2510.03256) on trapped magnetic flux decay in intercalated graphite samples supports the proposition.

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