Materials design, synthesis, and transport properties of disordered rare-earth Zintl bismuthides with the anti-Th₃P₄ structure type

Abstract

The synthesis, structural elucidation, and transport properties of the extended series Ca4–xRExBi3 (RE = Y, La–Nd, Sm, Gd–Tm, Lu; x ≈ 1) and Ca4–xRExBi3–δSbδ (RE = La, Ho, Er, Lu;...

Observation of Anomalously High Seebeck Coefficients in the Family of Zintl Phase Semiconductors Ca10RECdSb9 (RE = Rare-Earth Metal)

“…Although the value achieved at 600 K is close to that of Ca 10 SmCdSb 9 , a striking difference between these two phases lies in their electrical transport properties captured in Figure b,d. The degenerate semiconducting state in Ca 10 NdCdSb 9 makes it satisfy one of the important criteria of a good thermoelectric material candidate. − This observation also attests to the fact that the structural/elemental configuration in the present case has resulted in near-optimal tuning conditions. This line of thought is further supported by the Hall coefficient measurements, which yield the following Hall concentrations n H at 300 K: 1.23 × 10 16 cm –3 (Ca 10 LuCdSb 9 ), 4.04 × 10 17 cm –3 (Ca 10 CeCdSb 9 ), 1.45 × 10 18 cm –3 (Ca 10 SmCdSb 9 ), and 4.68 × 10 20 cm –3 (Ca 10 NdCdSb 9 ).…”

Structural Complexity and Tuned Thermoelectric Properties of a Polymorph of the Zintl Phase Ca2CdSb2 with a Non-centrosymmetric Monoclinic Structure

“…Here ρ­( T ) attains a magnitude of ca. 6.5 mΩ cm at 300 K and which gradually increases to 7.8 mΩ cm at 500 K. The low magnitude of ρ­( T ) in Ca 2– x Lu x CdSb 2 (-m) is comparable to those of several excellent and candidate thermoelectric materials ,,, and is beneficial toward the realization of enhanced thermoelectric figure of merit zT = S 2 σ/(κ e + κ l ) at a given operating temperature T . Here, S , σ, κ e , and κ l are the Seebeck coefficient, electrical conductivity, electronic thermal conductivity, and lattice thermal conductivity, respectively …”

Exploiting the fraternal twin nature of thermoelectrics and topological insulators in Zintl phases as a tool for engineering new efficient thermoelectric generators

“…69 among many others (RE = rare-earth metal). [70][71][72][73][74][75][76] Besides the exploration of the Zintl phase materials for TE applications, an increasingly growing trend is the observation of topological properties of matter in a number of these phases. [77][78][79][80] Several excellent TE materials are known to possess nontrivial topological properties as it appears both favor the same material properties such as strong spin orbit coupling (SOC) and narrow band gap.…”

“…58–63 In recent years our group has contributed significantly to the discovery and characterization of several other families of Zintl phases, including AE 2 CdP 2 , 64 Eu 3 InAs 3 , 65 Ca 14 AlBi 11 , 66 Ca 10 M Sb 9 ( M = Ga, In, Mn, Zn), 67 Ca 9– x RE x Cd 4 Sb 9 , 68 and Ca 10 RE CdSb 9 , 69 among many others ( RE = rare-earth metal). 70–76…”