Quartic Anharmonicity of Rattlers and Its Effect on Lattice Thermal Conductivity of Clathrates from First Principles

2017/10/31 by Terumasa Tadano, Shinji Tsuneyuki
Chemistry · Earth and Planetary Sciences · Materials Science · Physics and Astronomy · #Ab initio #Advanced Thermoelectric Materials and Devices #Anharmonicity #Chemistry #Clathrate hydrate #Condensed matter physics #High-pressure geophysics and materials #Hydrate #Lattice (music) #Materials science #Phonon #Physics #Quantum mechanics #Quartic function #Scattering #Thermal conductivity #Thermal properties of materials #Thermodynamics #cond-mat.mtrl-sci

paper · pdf · doi:10.1103/physrevlett.120.105901

published as Phys. Rev. Lett. 120, 105901 (2018) · 15 pages, 17 figures

openalex publication_date 2018/03/07 · arxiv created 2018/03/10 · arxiv updated 2018/03/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

We investigate the role of the quartic anharmonicity in the lattice dynamics and thermal transport of the type-I clathrate Ba₈Ga₁₆Ge₃₀ based on ab initio self-consistent phonon calculations. We show that the strong quartic anharmonicity of rattling guest atoms causes the hardening of vibrational frequencies of low-lying optical modes and thereby affects calculated lattice thermal conductivities κ_L significantly, resulting in an improved agreement with experimental results including the deviation from κ_L∝T^-1 at high temperature. Moreover, our static simulations with various different cell volumes shows a transition from crystal-like to glasslike κ_L around 20 K. Our analyses suggest that the resonance dip of κ_L observed in clathrates with large guest free spaces is attributed mainly to the strong three-phonon scattering of acoustic modes along with the presence of higher-frequency dispersive optical modes.

Citations

• Projector augmented-wave method
• Semiconducting Ge clathrates: Promising candidates for thermoelectric applications
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• Generalized Gradient Approximation Made Simple
• VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data
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• Efficient iterative schemes forab initiototal-energy calculations using a plane-wave basis set
• Entropy Driven Stabilization of Energetically Unstable Crystal Structures Explained from First Principles Theory
• Glasslike versus crystalline thermal conductivity in carrier-tunedBa8Ga16X30clathrates(X=Ge,Sn)
• Possible mechanism for glass-like thermal conductivities in crystals with off-center atoms
• Statistical Learning with Sparsity: The Lasso and Generalizations
• First-Principles Lattice Dynamics Method for Strongly Anharmonic Crystals
• The Elements of Statistical Learning: Data Mining, Inference, and Prediction