Phonon scattering due to van der Waals forces in the lattice thermal conductivity of Bi{sub 2}Te{sub 3} thin films

Journal Article · Wed Jan 07 00:00:00 EST 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4905294· OSTI ID:22399229

Mohamed, Mohamed; Ravaioli, Umberto ^[1]; Aksamija, Zlatan ^[2]

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1. Electrical and Computer Engineering, University of Illinois, Urbana, Illinois 61801 (United States)
2. Electrical and Computer Engineering, University of Massachusetts, Amherst, Massachusetts 01003 (United States)

In this work, we calculate the thermal conductivity of layered bismuth telluride (Bi{sub 2}Te{sub 3}) thin films by solving the Boltzmann transport equation in the relaxation-time approximation using full phonon dispersion and compare our results with recently published experimental data and molecular dynamics simulation. The group velocity of each phonon mode is readily extracted from the full phonon dispersion obtained from first-principle density-functional theory calculation and is used along with the phonon frequency to compute the various scattering terms. Our model incorporates the typical interactions impeding thermal transport (e.g., umklapp, isotope, and boundary scatterings) and introduces a new interaction capturing the reduction of phonon transmission through van der Waals interfaces of adjacent Bi{sub 2}Te{sub 3} quintuple layers forming the virtual superlattice thin film. We find that this novel approach extends the empirical Klemens-Callaway relaxation model in such anisotropic materials and recovers the experimental anisotropy while using a minimal set of parameters.

• OSTI ID: 22399229
• Journal Information: Journal of Applied Physics, Vol. 117, Issue 1; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANISOTROPY
APPROXIMATIONS
BISMUTH
BISMUTH TELLURIDES
BOLTZMANN EQUATION
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
DENSITY FUNCTIONAL METHOD
INTERFACES
MOLECULAR DYNAMICS METHOD
PHONONS
RELAXATION TIME
SCATTERING
SUPERLATTICES
THERMAL CONDUCTIVITY
THIN FILMS
VAN DER WAALS FORCES