Observation of Temperature Dependent Atomic Off‐Centering in High Entropy Cubic I‐V‐VI<sub>2</sub>/IV‐VI Alloys with Ultralow Thermal Conductivity
Bibliographic record
Abstract
Abstract I‐V‐VI2/IV‐VI compounds and their alloys are of great interest in the field of thermoelectricity due to their unique high‐symmetry crystal structures and unexpectedly low thermal conductivity, which is closely related to the off‐centering effect in the cubic lattice. However, the influence of such an effect on thermal transport across different temperatures remains largely elusive. Herein, using in situ pair distribution function analysis, it is directly observed that the sustained low thermal conductivity in n‐type (AgBiSe2)1‐x(PbS)x alloys stem from the dynamic intelligent switching of local structural distortions over wide temperature windows for the first time. Under ambient conditions, the local off‐centering of central atoms dominates the phonon scattering, while at high temperatures, the geometrical configuration of the ligands predominantly modulates thermal conductivity due to lattice expansion and diminished cation off‐centering. The complementary synergistic effect leads to an ultralow thermal conductivity (<0.64 W m−1 K−1) for (AgBiSe2)0.65(PbS)0.35 across the entire working temperature range and yields a lattice thermal conductivity of only 0.33 W m−1 K−1 at 800 K approaching the glass limit. Atomic‐scale insights into the thermal conductivity mechanism of I‐V‐VI2/IV‐VI alloys provide important guidance for designing high‐efficiency thermoelectric materials over broad operational temperature ranges.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".