Thermoelectric semiconductors (Zn-Sb materials)

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Presentation transcript:

Thermoelectric semiconductors (Zn-Sb materials) Salient questions Polarity of frameworks, quantification of polarity? Distinction to Zintl phases? change of thermoelectric (semiconductor) properties with polarity? InSb GaSb Increasing polarity on Zn Zn-Sb ZnAs Zn-Te Zn-Se Mg-Sb (Mg3Sb2) Li-Sb (Li2Sb) Increasing polarity on Sb → Zintl phases

Structures: - Zinc blende (sphalerite): GaSb, InSb, ZnSe, ZnTe - ZnSb structure: ZnSb, ZnAs (high pressure phase) - Anti-La2O3: Mg3Sb2 - Mg2Ga structure: Li2Sb sphalerite ZnSb, ZnAs Zn-Zn bond!

Mg3Sb2 Li2Sb

Start electronic structure calculations relax structural parameters Calculate electronic band structures/density of states Calculate charge density distributions/difference charge densities Extract “polarity” - what is a good measure? Bader charges, etc? Check literature Extract semiconductor properties from electronic structure -what and how? Approaches/approximations?