High-Pressure Hydrogen Sulfide from First Principles: A Strongly Anharmonic Phonon-Mediated Superconductor - Spectroscopie des nouveaux états quantiques Accéder directement au contenu
Article Dans Une Revue Physical Review Letters Année : 2015

High-Pressure Hydrogen Sulfide from First Principles: A Strongly Anharmonic Phonon-Mediated Superconductor

Matteo Calandra
Chris J . Pickard
  • Fonction : Auteur
Joseph Nelson
  • Fonction : Auteur
Richard J. Needs
  • Fonction : Auteur
Hanyu Liu
  • Fonction : Auteur
Yunwei Zhang
  • Fonction : Auteur
Yanming Ma
  • Fonction : Auteur
Richard Needs
  • Fonction : Auteur

Résumé

We use first principles calculations to study structural, vibrational and superconducting properties of H$_2$S at pressures $P\ge 200$ GPa. The inclusion of zero point energy leads to two different possible dissociations of H$_2$S, namely 3H$_2$S $\to$ 2H$_3$S + S and 5H$_2$S $\to$ 3H$_3$S + HS$_2$, where both H$_3$S and HS$_2$ are metallic. For H$_3$S, we perform non-perturbative calculations of anharmonic effects within the self-consistent harmonic approximation and show that the harmonic approximation strongly overestimates the electron-phonon interaction ($\lambda\approx 2.64$ at 200 GPa) and T$_c$. Anharmonicity hardens HS bond-stretching modes and softens H--S bond-bending modes. As a result, the electron-phonon coupling is suppressed by $30\%$ ($\lambda\approx 1.84$ at 200 GPa). Moreover, while at the harmonic level T$_c$ decreases with increasing pressure, the inclusion of anharmonicity leads to a T$_c$ that is almost independent of pressure. High pressure hydrogen sulfide is a strongly anharmonic superconductor.

Dates et versions

hal-02358114 , version 1 (11-11-2019)

Identifiants

Citer

Ion Errea, Matteo Calandra, Chris J . Pickard, Joseph Nelson, Richard J. Needs, et al.. High-Pressure Hydrogen Sulfide from First Principles: A Strongly Anharmonic Phonon-Mediated Superconductor. Physical Review Letters, 2015, 114 (15), ⟨10.1103/PhysRevLett.114.157004⟩. ⟨hal-02358114⟩
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