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arXiv · 2407.12922

Fundamental limits on the electron-phonon coupling and superconducting $T_c$

Dmitrii V. Semenok·Boris L. Altshuler·Emil A. Yuzbashyan
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Abstract

Fundamental upper bounds on the electron-phonon interaction strength and superconducting transition temperature $T_c$ in metals are established based on the intrinsic instability of the equilibrium between electrons and the crystal lattice under strong interaction. This instability explains why observed electron-phonon coupling constants are limited to $\lambda \lesssim 4$. The theory also accounts for the mechanism of metastable superconductivity with enhanced $T_c$, which emerges near the instability threshold. Based on theoretical analysis and comparison with experimental data, room-temperature phonon-mediated superconductivity is found to be feasible exclusively in hydrogen compounds.

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Dmitrii V. Semenok, Boris L. Altshuler, Emil A. Yuzbashyan. 2024-07-17. Fundamental limits on the electron-phonon coupling and superconducting $T_c$. https://doi.org/10.1002/adma.202507013

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