[en] Fe2YZ full-Heusler compounds were recently predicted to exhibit very large thermoelectric power factors [Phys. Rev. Lett. 114, 136601 (2015)]. Combining first-principles density functional theory calculations within a hybrid functional approach and Boltzmann semi-classical transport theory, we investigate the limits of the rigid band doping approximation, and the properties of heavily n-type doped full-Heusler Fe2YZ1-xAx compounds. Using a supercell approach and including explicit dopant impurities, we recover in some cases giant thermoelectric power factors, as previously predicted within the rigid band approximation. In others the effect on the electronic structure is very different from rigid shifts. Interestingly, we find that some systems present a magnetic instability consistent with the Stoner model, and evolve towards a ferromagnetic half-metallic ground state, with a strongly modified power factor. Our results show the promise of the heavily-doped phases of the studied Fe2YZ1-xAx compounds for Seebeck and spin-dependent Seebeck applications.
Research Center/Unit :
CESAM - Complex and Entangled Systems from Atoms to Materials - ULiège
Disciplines :
Physics
Author, co-author :
Lemal, Sébastien ; Université de Liège > Département de physique > Physique théorique des matériaux
Ricci, Fabio ; Université de Liège > Département de physique > Physique théorique des matériaux
Verstraete, Matthieu ; Université de Liège > Département de physique > Physique des matériaux et nanostructures
Ghosez, Philippe ; Université de Liège > Département de physique > Physique théorique des matériaux
Language :
English
Title :
Thermoelectric properties of heavily-doped Fe2YZ full-Heusler compounds
Publication date :
31 July 2017
Number of pages :
A0
Event name :
International Conference of Thermoelectrics 2017
Event date :
31 juillet 2017 - 3 août 2017
Audience :
International
Funders :
F.R.S.-FNRS - Fonds de la Recherche Scientifique [BE] Région wallonne [BE]