Table 2. Calculated 300 K lattice thermal conductivities (κ latt) of SnS2, Pnma and π-cubic SnS and Sn2S3, compared to values for PbTe, Pnma SnSe, and kesterite Cu2ZnSnS4 and Cu2ZnSnSe4 (CZTS/Se) from other calculations.43,45,62 Each row lists the thermal conductivities along each Cartesian direction together with the isotropic average κ iso. Values of κ iso calculated including isotope-scattering effects, assuming the natural atomic-mass variances for the constituent elements, are also given where possible, and experimental values are listed for comparison where available.5,63–66 The final column presents “anisotropy” values for each system, defined here as the ratio of the maximum and minimum diagonal components of the κ latt tensors.
| Compound |
κ
latt,300K [W m–1 K–1] |
Anisotropy | |||||
| κ xx | κ yy | κ zz | κ iso | κ iso,isotope | Expt. | ||
| SnS2 | 11.40 | 11.40 | 0.48 | 7.76 | 7.60 | — | 23.99 |
| SnS (Pnma) | 0.74 | 0.36 | 1.10 | 0.73 | 0.72 | 1.254 a | 3.02 |
| SnS (π-cubic) | — | — | — | 0.13 | 0.13 | — | — |
| Sn2S3 | 0.03 | 0.14 | 0.01 | 0.06 | 0.06 | — | 10.29 |
| PbTe | — | — | — | 2.5943 b | — | 1.99, 2.263,64 | — |
| SnSe (Pnma) | 1.44 | 0.53 | 1.88 | 1.2862 | 1.24 | 0.64 (κ xx/κ zz: 0.70, κ yy: 0.45)5 | 3.57 |
| Cu2ZnSnS4 | 1.75 | 1.75 | 1.57 | 1.6945 | 1.60 | 2.95, 4.765,66 c | 1.12 |
| Cu2ZnSnSe4 | 4.68 | 4.68 | 3.98 | 4.4445 | 4.36 | 3.7566 c | 1.18 |
aThe thermal-conductivity measurements in ref. 4 are given as κ tot = κ latt + κ el.
bFor consistency with the other calculations, we report the 300 K value from the κ latt,iso(T) curve computed at the 0 K lattice volume, as shown in Fig. 5.
cThe CZTS/Se lattice thermal conductivities reported in ref. 66 were measured slightly above 300 K.