Tl<sub>2</sub>Ag<sub>12</sub>Se<sub>7</sub>: A New pnp Conduction Switching Material with Extraordinarily Low Thermal Conductivity
Bibliographic record
Abstract
While continuing our investigations of thallium chalcogenides because of their outstanding thermoelectric properties, we discovered a new selenide with an interesting pnp switching behavior around 400 K. Tl 2 Ag 12 Se 7 was prepared via high temperature reaction from the elements in the stoichiometric ratio. This selenide crystallizes in a new structure type, namely a √3 × √3 × 1 super cell of the Zr 2 Fe 12 P 7 type, adopting space group P 3̅, a = b = 18.9153(18) Å, c = 4.3783(4) Å, and V = 1356.6(2) Å 3 ( Z = 3). The structure consists of a complex network of three-dimensionally connected AgSe 4 tetrahedra that include linear channels filled with thallium atoms. This material is a semiconductor with an experimentally derived activation gap of 0.8 eV and extraordinarily low thermal conductivity of <0.45 W m –1 K –1 . A reversible phase transition causes a pnp switch from p-type to n-type and back to p-type conduction beginning around 390 K, with the thermopower changing fast from +230 μV K –1 at 390 K to −230 μV K –1 at 410 K, and then back up to +75 μV K –1 at 420 K.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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".