Transport Phenomena of Ferroelectric Solid Solutions (GeTe)_1−<i>x</i>((Ag₂Te)_1−<i>y</i>(Sb₂Te₃)_<i>y</i>)_<i>x</i> with <i>y</i> = 0.60, 0 ≦ <i>x</i> ≦ 1 at 300 K

Abstract

Abstract The variation of the transport coefficients at 300 K, Seebeck coefficient (α), specific resistivity or conductivity (ϱ = I/s̀), Hall coefficient ( R H ), and thermal conductivity ( K ) with the composition ( x ) for solid solution (GeTe) 1− x ((Ag 2 Te) 1− y (Sb 2 Te 3 ) y ) x ) with y = 0.60 is investigated. The Hall coefficient decreases, reaches at x = 0.40 the minimal value and increases then up to x = 1, but the variation of the other transport coefficients are monotonous with composition: α and ε increase but K decreases with composition. The results are interpreted qualitatively on the base of the band edge model of GeTe with splitting of the L‐ and ∑‐valleys of the Brillouin zone (BZ) at the ferroelectric O h –C 3v phase transition and the complicated form of the surfaces of constant energy.