First-principles description of anomalously low lattice thermal conductivity in thermoelectric Cu-Sb-Se ternary semiconductors

Yongsheng Zhang*, Eric Skoug, Jeffrey Cain, Vidvuds Ozoliņ, Donald Morelli, C. Wolverton

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

160 Scopus citations

Abstract

Experimental measurements have recently shown that Cu 3SbSe 3 exhibits anomalously low and nearly temperature-independent lattice thermal conductivity, whereas Cu 3SbSe 4 does not exhibit this anomalous behavior. To understand this strong distinction between these two seemingly similar compounds, we perform density functional theory calculations of the vibrational properties of these two semiconductors within the quasiharmonic approximation. We observe strikingly different behavior in the two compounds: almost all the acoustic-mode Grüneisen parameters are negative in Cu 3SbSe 4, whereas almost all are positive in Cu 3SbSe 3 throughout their respective Brillouin zones. The average of the square of the Grüneisen parameter for the acoustic mode in Cu 3SbSe 3 is larger than that of Cu 3SbSe 4, which theoretically confirms that Cu 3SbSe 3 has a stronger lattice anharmonicity than Cu 3SbSe 4. The soft frequency and high Grüneisen parameters in Cu 3SbSe 3 arise from the electrostatic repulsion between the lone s2 pair at Sb sites and the bonding charge in Sb-Se bonds. Using our first-principles- determined longitudinal and transverse acoustic-mode Grüneisen parameters, zone-boundary frequencies, and phonon group velocities, we calculate the lattice thermal conductivity using the Debye-Callaway model. The theoretical thermal conductivity is in good agreement with the experimental measurements.

Original languageEnglish (US)
Article number054306
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume85
Issue number5
DOIs
StatePublished - Feb 21 2012

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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