Stacking-dependent thermoelectric transport in layered Sc_2Si_2Te_6 from first principles
Fuente:
arXiv
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2026
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866917479118274560 |
|---|---|
| author | Han, Zhongjuan Xiong, Wu Xia, Zhonghao Huang, WeiTong He, Jiangang |
| author_facet | Han, Zhongjuan Xiong, Wu Xia, Zhonghao Huang, WeiTong He, Jiangang |
| contents | Stacking polymorphism is a common characteristic of van der Waals layered materials and can substantially modify their physical properties. Here, based on first-principles calculations combined with electron and phonon transport theories, we systematically investigate the thermodynamic stability, electronic structure, lattice dynamics, and thermoelectric performance of Sc_2Si_2Te_6 with three high-symmetry stacking sequences, namely, AA, AB, and ABC. We find that the AA- and AB-stacked structures are nearly degenerate in energy with the experimentally reported ABC phase, and that the maximum sliding barrier among these stacking sequences is only about 10~meV/atom, thereby accounting for the stacking faults observed experimentally. These three stacking sequences exhibit distinct electronic structures, with the conduction-band minimum being highly sensitive to the stacking sequence. As a consequence, the conduction-band degeneracies are 12, 2, and 8 for the ABC, AA, and AB stackings, respectively, leading to markedly different electronic transport properties near the band edge. The lattice thermal conductivity is governed primarily by three-phonon scattering, whereas four-phonon scattering provides an additional reduction, particularly in the ABC stacking. Among the three structures, the AB stacking exhibits the lowest lattice thermal conductivity owing to its stronger three-phonon scattering and lower phonon group velocity. As a result, the maximum thermoelectric figure of merit, ZT, is achieved in the ABC structure, followed closely by the AB structure, whereas the AA structure shows a substantially reduced value. These results demonstrate that the stacking sequence exerts a non-negligible influence on the thermoelectric performance of Sc_2Si_2Te_6 and suggest that suppressing the formation of the AA stacking is important for achieving high thermoelectric performance. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_09529 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Stacking-dependent thermoelectric transport in layered Sc_2Si_2Te_6 from first principles Han, Zhongjuan Xiong, Wu Xia, Zhonghao Huang, WeiTong He, Jiangang Materials Science Stacking polymorphism is a common characteristic of van der Waals layered materials and can substantially modify their physical properties. Here, based on first-principles calculations combined with electron and phonon transport theories, we systematically investigate the thermodynamic stability, electronic structure, lattice dynamics, and thermoelectric performance of Sc_2Si_2Te_6 with three high-symmetry stacking sequences, namely, AA, AB, and ABC. We find that the AA- and AB-stacked structures are nearly degenerate in energy with the experimentally reported ABC phase, and that the maximum sliding barrier among these stacking sequences is only about 10~meV/atom, thereby accounting for the stacking faults observed experimentally. These three stacking sequences exhibit distinct electronic structures, with the conduction-band minimum being highly sensitive to the stacking sequence. As a consequence, the conduction-band degeneracies are 12, 2, and 8 for the ABC, AA, and AB stackings, respectively, leading to markedly different electronic transport properties near the band edge. The lattice thermal conductivity is governed primarily by three-phonon scattering, whereas four-phonon scattering provides an additional reduction, particularly in the ABC stacking. Among the three structures, the AB stacking exhibits the lowest lattice thermal conductivity owing to its stronger three-phonon scattering and lower phonon group velocity. As a result, the maximum thermoelectric figure of merit, ZT, is achieved in the ABC structure, followed closely by the AB structure, whereas the AA structure shows a substantially reduced value. These results demonstrate that the stacking sequence exerts a non-negligible influence on the thermoelectric performance of Sc_2Si_2Te_6 and suggest that suppressing the formation of the AA stacking is important for achieving high thermoelectric performance. |
| title | Stacking-dependent thermoelectric transport in layered Sc_2Si_2Te_6 from first principles |
| topic | Materials Science |
| url | https://arxiv.org/abs/2605.09529 |