The six new compounds Tl 2CdGeTe 4, Tl 2CdSnTe 4, Tl 2HgGeTe 4, Tl 2HgSnTe 4, Tl 2MnGeTe 4, and Tl 2-MnSnTe 4 have been synthesized. All six compounds are isostructural and crystallize in the tetragonal space group I-42m with a ≈ 8.3 Å and c ≈ 7.1 Å. The structure is composed of chains of composition [AXTe 4] 2- separated by Tl 1+ ions, an ordered superstructure of the TlSe structure type. In addition to their syntheses and crystal structures, we report the calculated electronic structures of these six compounds and of the related compounds KInTe 2 and TlInTe 2. We measured the thermoelectric properties (electrical resistivity, thermopower, and thermal conductivity) of Tl 2CdGeTe 4, Tl 2CdSnTe 4, Tl 2HgGeTe 4, and Tl 2-HgSnTe 4. These compounds are semiconductors with very low thermal conductivities and moderately high thermopowers. However, as currently prepared they have resistivities that are too high for thermoelectric applications. Magnetic susceptibility and resistivity measurements show Tl 2MnGeTe 4 and Tl 2MnSnTe 4 to be Mott insulators, in agreement with spin-polarized band structure calculations.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Materials Chemistry