Band gap (Eg ) as a function of Pauling scale electronegativity difference between the Pn and the Ae elements.
Calculated electronic DOS as obtained using the TB-mBJ functional for the Ca (top), Sr (middle), and Ba (bottom) compounds.
Calculated band structures as obtained using the TB-mBJ functional for the Ca (top), Sr (middle), and Ba (bottom) compounds.
Calculated band structure of Mg3Sb2 as obtained using the TB-mBJ functional.
Calculated optical absorption spectra showing both in plane (x) and out-of-plane polarizations for Mg3Sb2 (top), and direction averaged for the Ca (middle top), Sr (middle bottom), and Ba (bottom) cases. A Lorentzian broadening of 0.1 eV was applied.
Calculated direction averaged thermopower, S(T) for the p (above axis) and n (below axis) compounds at 300 K and 900 K as a function of doping level. The As compounds are in the top panel, Sb compounds in the middle, and Bi compounds in the lower panel. Data for the Ae = Ca compounds were reported previously in Ref. 8 at 300 K and 800 K.
Calculated phonon dispersions (in THz) for hexagonal CaMg2Sb2 along high symmetry directions.
Calculated phonon densities-of-states for CaMg2Sb2.
Structural parameters used in the present calculations. The hexagonal lattice parameters, a and c are experimental data from literature, while the internal co-ordinates are determined by energy minimization. The band gaps, Eg , are as obtained with the TB-mBJ functional. Data for the Ca compounds were presented previously, in Ref. 8 . Pauling scale electronegativities, and are given for the Ae and Pn sites, respectively.
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