Ab initio computational study on the lattice thermal conductivity of Zintl clathrates [Si$_{19}$P$_{4}$]Cl$_{4}$ and Na$_{4}$[Al$_{4}$Si$_{19}$]

Ville J. Härkönen; Antti J. Karttunen

doi:10.1103/PhysRevB.94.054310

paper

Ab initio computational study on the lattice thermal conductivity of Zintl clathrates [Si $_{19}$ P $_{4}$ ]Cl $_{4}$ and Na $_{4}$ [Al $_{4}$ Si $_{19}$ ]

arXiv:1604.07050 · doi:10.1103/PhysRevB.94.054310

Abstract

The lattice thermal conductivity of silicon clathrate framework Si $_{23}$ and two Zintl clathrates, [Si $_{19}$ P $_{4}$ ]Cl $_{4}$ and Na $_{4}$ [Al $_{4}$ Si $_{19}$ ], is investigated by using an iterative solution of the linearized Boltzmann transport equation (BTE) in conjuntion with ab initio lattice dynamical techniques. At 300 K, the lattice thermal conductivities for Si $_{23}$ , [Si $_{19}$ P $_{4}$ ]Cl $_{4}$ , and Na $_{4}$ [Al $_{4}$ Si $_{19}$ ] were found to be 43 W/(m K), 25 W/(m K), and 2 W/(m K), respectively. In the case of Na $_{4}$ [Al $_{4}$ Si $_{19}$ ], the order-of-magnitude reduction in the lattice thermal conductivity was found to be mostly due to relaxation times and group velocities differing from Si $_{23}$ and [Si $_{19}$ P $_{4}$ ]Cl $_{4}$ . The difference in the relaxation times and group velocities arises primarily due to the phonon spectrum at low frequencies, resulting eventually from the differences in the second-order interatomic force constants (IFCs). The obtained third-order IFCs were rather similar for all materials considered here.

11 pages, 8 figures

Ab initio computational study on the lattice thermal conductivity of Zintl clathrates [Si $_{19}$ P $_{4}$ ]Cl $_{4}$ and Na $_{4}$ [Al $_{4}$ Si $_{19}$ ]

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Ab initio computational study on the lattice thermal conductivity of Zintl clathrates [Si19​P4​]Cl4​ and Na4​[Al4​Si19​]

Abstract

References in corpus (10)

Cited by in corpus (7)

Ab initio computational study on the lattice thermal conductivity of Zintl clathrates [Si $_{19}$ P $_{4}$ ]Cl $_{4}$ and Na $_{4}$ [Al $_{4}$ Si $_{19}$ ]