title: Intrinsically minimal thermal conductivity in cubic I-V-VI2 semiconductors.
abstract: We report measurements of the thermal conductivity of high-quality crystals of the cubic I-V-VI2 semiconductors AgSbTe2 and AgBiSe2. The thermal conductivity is temperature independent from 80 to 300 K at a value of approximately 0.70 W/mK. Heat conduction is dominated by the lattice term, which we show is limited by umklapp and normal phonon-phonon scattering processes to a value that corresponds to the minimum possible, where the phonon mean free path equals the interatomic distance. Minimum thermal conductivity in cubic I-V-VI2 semiconductors is due to an extreme anharmonicity of the lattice vibrational spectrum that gives rise to a high Grüneisen parameter and strong phonon-phonon interactions. Members of this family of compounds are therefore most promising for thermoelectric applications, particularly as p-type materials.
authors.affiliation: Department of Chemical Engineering & Materials Science, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: D T
authors.initials: DT
authors.lastname: Morelli
authors.forename: V
authors.initials: V
authors.lastname: Jovovic
authors.forename: J P
authors.initials: JP
authors.lastname: Heremans