Quantum lattice dynamics and their importance in ternary superhydride clathrates

Abstract

The quantum nature of the hydrogen lattice in superconducting hydrides can have crucial effects on the material's properties. Taking a detailed look at the dynamic stability of the recently predicted BaSiH${}_8$ phase, we find that the inclusion of anharmonic quantum ionic effects leads to an increase in the critical dynamical pressure to $20\text{GPa}$ as compared to $5\text{GPa}$ within the harmonic approximation. We identify the change in the crystal structure due to quantum ionic effects to be the main driving force for this increase and demonstrate that this can already be understood at the harmonic level by considering zero-point energy corrections to the total electronic energy. In fact, the previously determined critical pressure of kinetic stability $p_{\text{kin}}=30\text{GPa}$ still poses a stricter bound for the synthesizability of BaSiH${}_8$ and similar hydride materials than the dynamical stability and therefore constitutes a more rigorous and accurate estimate for the experimental realizability of these structures.

10 pages, 5 figures. Revised manuscript with minor changes. Supplemental Material available on the journal website (open access)

References in corpus (16)

• Advanced capabilities for materials modelling with Quantum ESPRESSO
• Superconducting hydrides under pressure
• Design Principles for High Temperature Superconductors with Hydrogen-based Alloy Backbone at Moderate Pressure
• Towards high-throughput superconductor discovery via machine learning
• The Stochastic Self-Consistent Harmonic Approximation: Calculating Vibrational Properties of Materials with Full Quantum and Anharmonic Effects
• LaBH${}_8$: the first high-T${}_c$ low-pressure superhydride
• Superconductivity in sodalite-like yttrium hydride clathrates
• Prediction of high-Tc superconductivity in ternary lanthanum borohydrides
• Anharmonic phonon spectra of PbTe and SnTe in the self-consistent harmonic approximation
• High-throughput discovery of high-temperature conventional superconductors
• In-silico synthesis of lowest-pressure high-$T_{\text{c}}$ ternary superhydrides
• Tuning Chemical Precompression: Theoretical Design and Crystal Chemistry of Novel Hydrides in the Quest for Warm and Light Superconductivity at Ambient Pressures
• Phase Diagram and Superconductivity of Calcium Borohyrides at Extreme Pressures
• The road to room-temperature conventional superconductivity
• Full optimization of quasiharmonic free energy with anharmonic lattice model: Application to thermal expansion and pyroelectricity of wurtzite GaN and ZnO
• Materials under high pressure: A chemical perspective

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