Thermal Properties of β-Ga2O3 from First Principles

MRS Advances ◽  
2016 ◽  
Vol 1 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Marco D. Santia ◽  
Nandan Tandon ◽  
J. D. Albrecht
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Expansion ◽  
Bulk Modulus ◽  
Harmonic Approximation ◽  
Boltzmann Transport ◽  
Grüneisen Parameters ◽  
Optical Modes ◽  
Gruneisen Parameters

ABSTRACTThe thermal conductivity, bulk modulus, thermal expansion and heat capacity for bulk β-Ga2O3 are calculated from lattice dynamics using both a quasi-harmonic approximation and an anharmonic force-constant approach involving a solution of the linearized Boltzmann transport equation. The role of anharmonicity in β-Ga2O3 is determined to be small, which leads to the weak volume dependence of the calculated thermal conductivity. The negligible anharmonic contribution to the overall thermal conductivity is consistent with both thermal expansion measurements and also with comparisons between the quasi-harmonic and anharmonic methods. Phonon-mode-dependent Grüneisen parameters are found to be weakly dependent on temperature. Negative values of the mode Grüneisen parameters are found for certain low energy optical modes, but their net effect on the overall thermal expansion is insignificant. Bulk modulus as well as heat capacity are also given and found to be in agreement with experimental results.

Gruneisen parameters of bead-spring chains: MD simulation and theory

2020 ◽  
Vol 153 (24) ◽  
pp. 244903
Author(s):  
Craig S. Stevenson ◽  
John G. Curro ◽  
John D. McCoy
Keyword(s):  
Md Simulation ◽  
Grüneisen Parameters ◽  
Gruneisen Parameters
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