Strain-induced electronic band convergence: effect on the Seebeck coefficient of Mg2Si for thermoelectric applications.
The present theoretical study, performed using density-functional theory and Boltzmann transport theory formalisms, shows that under 2.246 % isotropic tensile strain, the two energy-lowest conduction bands of Mg2Si overlap. The two, threefold-degenerated orbitals become a unique, sixfold-degenerated orbital. It is demonstrated that such degeneracy implies an increase of the Seebeck coefficient, of the electrical conductivity, of the power factor, and in fine of the figure of merit.
MADIREL, Aix-Marseille University and CNRS, Avenue Normandie-Niemen, 13397, Marseille cedex 20, France.|Institut de Physique Nucléaire, Université Paris-Sud 11 and CNRS, 15 rue Georges Clémenceau, 91406, Orsay, France.
H
H
Balout
MADIREL, Aix-Marseille University and CNRS, Avenue Normandie-Niemen, 13397, Marseille cedex 20, France. pascal.boulet@univ-amu.fr.
P
http://orcid.org/0000-0001-8051-4287
P
Boulet
IM2NP, Aix-Marseille University and CNRS, Avenue Normandie-Niemen, 13397, Marseille cedex 20, France.
M-C
MC
Record
Band structures; Boltzmann transport theory; Density functional theory; Isotropic constraints; Silicides; Thermoelectricity