Brillouin zone unfolding method for effective phonon spectra

Abstract

Thermal properties are of great interest in modern electronic devices and nanostructures. Calculating these properties is straightforward when the device is made from a pure material, but problems arise when alloys are used. Specifically, only approximate bandstructures can be computed for random alloys and most often the Virtual Crystal Approximation (VCA) is used. Unfolding methods [T. B. Boykin, N. Kharche, G. Klimeck, and M. Korkusinski, J. Phys.: Condens. Matt. 19, 036203 (2007).] have proven very useful for tight-binding calculations of alloy electronic structure without the problems in the VCA, and the mathematical analogy between tight-binding and valence-force-field approaches to the phonon problem suggest they be employed here as well. However, there are some differences in the physics of the two problems requiring modifications to the electronic structure approach. We therefore derive a phonon alloy bandstructure (vibrational mode) approach based on our tight-binding electronic structure method, modifying the band-determination method to accommodate the different physical situation. Using the method, we study In${}_x$Ga${}_{1-x}$As alloys and find very good agreement with available experiments.

Main paper with attached supplemental material

References in corpus (10)

• Comparison of two methods for describing the strain profiles in quantum dots
• Unfolding first-principles band structures
• Recovering hidden Bloch character: Unfolding Electrons, Phonons, and Slabs
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• Unfolding method for the first-principles LCAO electronic structure calculations
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• Boosting electronic transport in carbon nanotubes by isotopic disorder
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• Unfolding the electronic structure of Ca${}_{10}$(Fe${}_{1-x}$Pt${}_x$As)${}_{10}$(Pt${}_n$As${}_8$)

Cited by in corpus (9)

• Mode-decomposition based on crystallographic symmetry in the band-unfolding method
• Phonon Unfolding: A program for unfolding phonon dispersions of materials
• Temperature-dependent phonon spectra of magnetic random solid solutions
• Unfolding energy spectra of multi-periodicity materials
• Universal Behavior of Strain in Quantum Dots
• Success and breakdown of the T-matrix approximation for phonon-disorder scattering
• Phonon dispersions throughout the iron spin crossover in ferropericlase
• Mapping Phonon Modes from Reduced-Dimensional to Bulk Systems
• Negative Refraction of Terahertz Phonons via Interfacial Momentum Compensation