Coupled polaron-phonon effects on Seebeck coefficient and lattice conductivity of B13C2 from first principles
- Coupled polaron-phonon effects on Seebeck coefficient and lattice conductivity of B13C2 from first principles
- 김형철; 매서드 카비아니
- Seebeck coefficient; Lattice conductivity; Lattice dynamics; Density functional theory; Boron carbides; Polaron; Phonon
- Issue Date
- Physical review B, Condensed matter and materials physics
- VOL 87, NO 15, 155133-1-155133-6
- The anomalous temperature-independent behavior of the Seebeck coefficient and the lattice thermal
conductivity of B13C2 are explained through polaron and phonon evolutions found using ab initio molecular
dynamics (AIMD). Analyses of lattice dynamics show that the unique icosahedron structures dominate the
optical phonon modes and CBC intericosahedral bonds dominate the local acoustic vibration. We identify that
the temperature-induced Jahn-Teller distortion and electron-phonon coupling in icosahedron structures create
small polarons (i.e., charge trapping and phonon softening). We also verify that large-displacement chain atoms
scatter heat-conducting phonons. Using equilibrium and nonequilibrium AIMD methods (including entropy and
energy analyses), we predict the Seebeck coefficient and its components as well as the lattice thermal conductivity,
and we find good agreement with experiments. Softened and localized phonons make a significant vibrational
contribution to the Seebeck coefficient and allow for an amorphous-like lattice thermal conductivity.
- Appears in Collections:
- KIST Publication > Article
- Files in This Item:
There are no files associated with this item.
- RIS (EndNote)
- XLS (Excel)
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.