Anharmonic theory of superconductivity in the high-pressure materials

Abstract

Electron-phonon superconductors at high pressures have displayed the highest values of critical superconducting temperature $T_c$ on record, now rapidly approaching room temperature. Despite the importance of high-$P$ superconductivity in the quest for room-temperature superconductors, a mechanistic understanding of the effect of pressure and its complex interplay with phonon anharmonicity and superconductivity is missing, as numerical simulations can only bring system-specific details clouding out key players controlling the physics. Here we develop a minimal model of electron-phonon superconductivity under an applied pressure which takes into account the anharmonic decoherence of the optical phonons. We find that $T_c$ behaves non-monotonically as a function of the ratio $\Gamma /{\omega }_0$, where $\Gamma$ is the optical phonon damping and ${\omega }_0$ the optical phonon energy at zero pressure and momentum. Optimal pairing occurs for a critical ratio $\Gamma /{\omega }_0$ when the phonons are on the verge of decoherence ("diffuson-like" limit). Our framework gives insights into recent experimental observations of $T_c$ as a function of pressure in the complex BCS material TlInTe${}_2$.

References in corpus (8)

• Hydrogen sulphide at high pressure: a strongly-anharmonic phonon-mediated superconductor
• Superconducting hydrides under pressure
• First-Principles Lattice Dynamics Method for Strongly Anharmonic Crystals
• Nonequilibrium Green's function method for phonon-phonon interaction and ballistic-diffusive thermal transport
• Anharmonic phonon damping enhances the $T_c$ of BCS-type superconductors
• Glass-induced enhancement of superconducting $T_c$: Pairing via dissipative mediators
• The higher superconducting transition temperature T${}_c$ and the functional derivative of T${}_c$ with ${\alpha }^{2}F(\omega )$ for electron-phonon superconductors
• Origin of superconductivity and giant phonon softening in TlInTe${}_2$ under pressure

Cited by in corpus (9)

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• Anharmonic theory of superconductivity and its applications to emerging quantum materials
• Predicting plasticity of amorphous solids from instantaneous normal modes
• Pressure weakens coupling strength in In and Sn elemental superconductors
• Turning non-superconducting elements into superconductors by quantum confinement and proximity
• Estimation of Grüneisen parameter of high-entropy-alloy-type functional materials
• Pressure-induced concurrent amorphization and superconductivity in topological material NbNiTe5