Predicted Electronic and Thermodynamic Properties of a Newly Discovered Zn₈Sb₇ Phase

Abstract

A new binary compound, Zn8Sb7, has recently been prepared in nanoparticulate form via solution synthesis. No such phase is known in the bulk phase diagram; instead, one would expect phase separation to the good thermoelectric semiconductors ZnSb and Zn4Sb3. Here, density functional calculations are employed to determine the free energies of formation, including effects from vibrations and configurational disorder, of the relevant phases, yielding insight into the phase stability of Zn8Sb7. Band structure calculations predict Zn8Sb7, much like ZnSb and Zn4Sb3, to be an intermetallic semiconductor with similar thermoelectric properties. If sufficient entropy or surface energy exists to stabilize the bulk material, it would be stable in a limited temperature window at high temperature.

Low‐Cost High‐Performance Zinc Antimonide Thin Films for Thermoelectric Applications

“…[ 6 , 22 , 23 ] Recently, a new Zn 8 Sb 7 phase was identifi ed experimentally [ 24 ] and theoretical calculations have been used to estimate the physical properties and stability of this phase. [ 25 ] In the present study ZnSb fi lms as well as two completely new meta-stable crystalline phases of zinc antimonide were directly deposited on silica substrates by a co-sputtering method. After post-annealing treatments at 573 K, the two new phases transformed into Zn 4 Sb 3 + ZnSb and single phase Zn 4 Sb 3 fi lms, respectively.…”

Impurity band conduction in the thermoelectric material ZnSb

“…• C makes it difficult to produce either perfect single crystal or homogeneous polycrystalline samples from a molten solution. The recent studies have discovered phases that were unknown previously: Zn 6−δ Sb 5 , which is a product when Zn 4 Sb 3 undergoes a transition below 767 K (before β to γ) [62]; Zn 8 Sb 7 , which has high Seebeck coefficient and is entropically stable at high temperature [61]; and Zn 13 Sb 10 , which was obtained by using Zn 4 Sb 3 nanoparticle precursors [63]. The aforesaid compounds are predicted to be good thermoelectric materials as ZnSb and Zn 4 Sb 3 .…”

“…According to this determination, ZnSb has orthorhombic crystal structure, oP16, and belongs to the space group P bca No. 61. The structure of ZnSb has been studied and confirmed by different techniques, albeit gave slightly different interatomic distances [62,69,83,84].…”

Defect‐Controlled Electronic Properties in AZn2Sb2 Zintl Phases

“…The degree of electron transfer between cations and anions [9] has well documented influence on the transport properties of Zintl compounds. [7,[15][16][17][18][19] This suggests that Zintl phases, provided that the valence and conduction bands do not overlap, should exhibit intrinsic semiconducting behavior with a low concentration of charge carriers. [7,[15][16][17][18][19] This suggests that Zintl phases, provided that the valence and conduction bands do not overlap, should exhibit intrinsic semiconducting behavior with a low concentration of charge carriers.…”