Designing vacancy-filled Heusler thermoelectric semiconductors by the Slater-Pauling rule

Discovery of triple half-Heusler Mg2VNi3Sb3 with low thermal conductivity

“…Nb 0.8 CoSb for NbCoSb and TiFe 1.5 Sb 55 in TiFeSb). Examples of such unstable metallic XYZ compositions containing impurity phases are NV = −1 based TiFeSb, 24 ZrRuSb, 25 TiRuSb, 26 HfRuSb 27 and NV = 1 based NbCoSb, 28 NbIrSb. 29 XRD results in ref.…”

Alloyed triple half-Heuslers: a route toward high-performance thermoelectrics with intrinsically low lattice thermal conductivity

“…The very low lattice thermal conductivities of Ti(Fe 0.5+ x Co 0.25 Cu 0.25− x )Sb samples can be ascribed to the increased structural disorder due to the random distribution of Fe/Co/Cu on the 4c site, 22–24 which is also reflected by their low sound velocities (Fig. 5a).…”

“…18,19 NbCoSn (k L = 9-10 W m −1 K −1 ), 20 TiCoSb (k L = 14-16 W m −1 K −1 ) and DHH TiFe 0.5 Ni 0.5 Sb (k L = 9 W m −1 K −1 ) 13,21 at 300 K. This result endorses the effectiveness of alloyed THH on reducing the lattice thermal conductivity and demonstrates a simple strategy to discover HH alloys with intrinsically low lattice thermal conductivity through the valence balanced approach. The very low lattice thermal conductivities of Ti(Fe 0.5+x -Co 0.25 Cu 0.25−x )Sb samples can be ascribed to the increased structural disorder due to the random distribution of Fe/Co/Cu on the 4c site, [22][23][24] which is also reected by their low sound velocities (Fig. 5a).…”

Structural Understanding of the Slater–Pauling Electron Count in Defective Heusler Thermoelectric TiFe1.5Sb as a Valence Balanced Semiconductor

“…Structures (a) and (b) are 17.3 meV/atom and 76 meV/atom higher than the ground-state R 3 m structure, respectively. These results suggest that the occupancies of the 4c and 4d sites and thereby the electronic properties of Slater–Pauling compositions like TiFe 1.5 Sb (e.g., MRu 1.5+ x Sb − ) could be sensitive to temperature. Experimentally, the Ru occupancies of the 4c and 4d sites in the semiconducting isoelectronic TiRu 1.5 Sb have been probed directly using atom-resolved high-angle annular dark-field (HAADF) images and were found to be unequal, which is in line with our analysis.…”

“…Recently, defective Heuslers TiFe 1.33 Sb, MRu 1.5+ x Sb, − and MCo 1.5 Sn (M = Ti, Zr, and Hf) with interstitial defects on the full-Heusler sites (see Figure ) were reported with very low lattice thermal conductivities (as low as 1.65 W m –1 K –1 at T = 300 K). Similar to most other half-Heuslersdefective or defect-freethese defective compounds also stabilize close to the semiconducting ground-state composition .…”