TY - JOUR
T1 - "A first-principles lattice dynamical study of type-I, type-II, and type-VIII silicon clathrates
AU - Norouzzadeh, Payam
AU - Myles, Charles
PY - 2016/1/29
Y1 - 2016/1/29
N2 - The pristine crystalline type-I, type-II, and type-VIII silicon clathrates have been studied using state of
the art first-principles calculations based on density functional theory and density functional perturbation theory. We apply quasi-harmonic approximation to study structural stability, the possibility of temperature or pressure driven
phase transitions, along with Gruneisen parameters,
coefficients of thermal expansion and thermal conductivities to estimate the degree of phonon anharmonicity for selected silicon clathrates. It is shown that a pressure-driven phase transition between type-I and type-II silicon clathrates may occur, and a temperature-driven phase transition between type-I and type-VIII Si clathrates at high
temperature is likely. We further show that the relatively high Gruneisen parameters (1.5, 1.65, and 1.29, respectively for Si46-I, Si136-II, Si46-VIII), the existence of negative regions in the thermal expansion coefficient curves and very low thermal conduct
AB - The pristine crystalline type-I, type-II, and type-VIII silicon clathrates have been studied using state of
the art first-principles calculations based on density functional theory and density functional perturbation theory. We apply quasi-harmonic approximation to study structural stability, the possibility of temperature or pressure driven
phase transitions, along with Gruneisen parameters,
coefficients of thermal expansion and thermal conductivities to estimate the degree of phonon anharmonicity for selected silicon clathrates. It is shown that a pressure-driven phase transition between type-I and type-II silicon clathrates may occur, and a temperature-driven phase transition between type-I and type-VIII Si clathrates at high
temperature is likely. We further show that the relatively high Gruneisen parameters (1.5, 1.65, and 1.29, respectively for Si46-I, Si136-II, Si46-VIII), the existence of negative regions in the thermal expansion coefficient curves and very low thermal conduct
M3 - Article
SP - 4538
JO - Journal of Materials Science
JF - Journal of Materials Science
ER -