dc.contributor.author | Eliassen, Simen Nut Hansen | |
dc.contributor.author | Katre, Anikta | |
dc.contributor.author | Madsen, Georg | |
dc.contributor.author | Persson, Clas | |
dc.contributor.author | Løvvik, Ole Martin | |
dc.contributor.author | Berland, Kristian | |
dc.date.accessioned | 2017-12-19T10:18:51Z | |
dc.date.available | 2017-12-19T10:18:51Z | |
dc.date.created | 2017-01-17T10:31:11Z | |
dc.date.issued | 2017 | |
dc.identifier.issn | 1098-0121 | |
dc.identifier.uri | http://hdl.handle.net/11250/2472795 | |
dc.description.abstract | In spite of their relatively high lattice thermal conductivity κℓ, the XNiSn (X=Ti, Zr, or Hf) half-Heusler compounds are good thermoelectric materials. Previous studies have shown that κℓ can be reduced by sublattice alloying on the X site. To cast light on how the alloy composition affects κℓ, we study this system using the phonon Boltzmann-transport equation within the relaxation time approximation in conjunction with density functional theory. The effect of alloying through mass-disorder scattering is explored using the virtual crystal approximation to screen the entire ternary TixZryHf1−x−yNiSn phase diagram. The lowest lattice thermal conductivity is found for the TixHf1−xNiSn compositions; in particular, there is a shallow minimum centered at Ti0.5Hf0.5NiSn with κℓ taking values between 3.2 and 4.1 W/mK when the Ti content varies between 20% and 80%. Interestingly, the overall behavior of mass-disorder scattering in this system can only be understood from a combination of the nature of the phonon modes and the magnitude of the mass variance. Mass-disorder scattering is not effective at scattering acoustic phonons of low energy. By using a simple model of grain boundary scattering, we find that nanostructuring these compounds can scatter such phonons effectively and thus further reduce the lattice thermal conductivity; for instance, Ti0.5Hf0.5NiSn with a grain size of L=100 nm experiences a 42% reduction of κℓ compared to that of the single crystal. | nb_NO |
dc.language.iso | eng | nb_NO |
dc.publisher | American Physical Society | nb_NO |
dc.title | Lattice thermal conductivity of TixZryHf1−x−yNiSn half-Heusler alloys calculated from first principles: Key role of nature of phonon modes | nb_NO |
dc.type | Journal article | nb_NO |
dc.type | Peer reviewed | nb_NO |
dc.description.version | publishedVersion | nb_NO |
dc.source.volume | 95 | nb_NO |
dc.source.journal | Physical Review B. Condensed Matter and Materials Physics | nb_NO |
dc.source.issue | 4 | nb_NO |
dc.identifier.doi | 10.1103/PhysRevB.95.045202 | |
dc.identifier.cristin | 1429314 | |
dc.relation.project | Notur/NorStore: NN9180K | nb_NO |
dc.relation.project | Norges forskningsråd: 228854 | nb_NO |
dc.description.localcode | © 2017 American Physical Society | nb_NO |
cristin.unitcode | 194,66,35,0 | |
cristin.unitname | Institutt for materialteknologi | |
cristin.ispublished | true | |
cristin.fulltext | original | |
cristin.qualitycode | 2 | |