Physical Transformation AtlasPTA
Pathway · p-0a69862796 · same energy form

Electric potential difference → Electrical work

Electric potential differenceEttingshausen effectTemperature gradientHeat conductionPhononsPhonon dragCharge carriersElectrical work

Epistemic state of the route

known constituent relations
7 / 7 established or replicated · weakest constituent established
constituent maturity floor
K4 · experimentally observed
search for this exact route
Not assessed — complete composition not searched.
recorded-pathway overlap
none recorded
route-level evidence
0 sources for the complete composition · 8 cited by the constituent steps
boundaries and interfaces
BOUNDARY compatible · no region transition

Explorematrix context · physics checks · steps · route evidence · constituent evidence · cite

Matrix context

D = disequilibrium row · C = coupling family column. A cell reads the state of the atlas for that pair.

D.06 × C.01 · Electric potential difference × Thermoelectricfamily: Thermoelectric

Typed bounds on this route

Every limit the atlas holds for this route, as constraint records: reached through bounded_by claims on the route's own entities. Hard bounds (an upper bound or a formula) decide the thermodynamic-bound check above; benchmarks, constitutive relations and resource limits are listed and never decisive. No prose limit exists anywhere (pass 42).

  • Carnot limit · formula-bound · hard, applies to this route
    η ≤ 1 − T_c/T_h for any heat engine between reservoirs at T_h and T_c

Steps

  1. 01
    electrical → thermal
    • a current in a conductor with a perpendicular magnetic field
    solid · conductor required · magnetic field required
    refs [1] [2]
  2. 02
    thermal → thermal
    refs [2] [3]
  3. 03
    thermal → thermal
    q = −κ · ∇T · thermal conductivity κ [W/(m K)]
    refs [4]
  4. 04
    Heat conduction —produces→ Phononsestablishedclaim record
    thermal → phonon
    • in an electrically insulating or semiconducting solid the heat current is carried by phonons
    solid
    refs [5]
  5. 05
    Phonons —drives→ Phonon dragestablishedclaim record
    phonon → electrical · loss to thermal
    • a phonon heat current in a semiconductor at low temperature
    solid · semiconductor required · cryogenic
    Phonon drag is a component of the same conductor's Seebeck coefficient, not a second converter in series with it: Yalamarthy et al. 2019 attribute up to 32 % (300 K) and 88 % (50 K) of the Seebeck coefficient of a thick AlGaN/GaN 2DEG to drag. The compiler therefore treats the heat-conduction → phonon-drag spelling as representation-equivalent to the thermoelectric generator.
    refs [6] [3] [7]
  6. 06
    Phonon drag —produces→ Charge carriersestablishedclaim record
    electrical → electrical
    refs [6] [3]
  7. 07
    Charge carriers —converts into→ Electrical workestablishedclaim record
    electrical → electrical · loss to thermal
    • carriers driven through an external load at the potential difference the source maintains
    refs [8]

Evidence for the complete composition · 0

No source on record for this exact composition. The sources below support the individual steps, not the route as a whole.

Evidence for the constituent relations · 8

  1. [1]
    A. von Ettingshausen, W. Nernst. Ueber das Auftreten electromotorischer Kräfte in Metallplatten, welche von einem Wärmestrome durchflossen werden und sich im magnetischen Felde befinden (1886)
    Annalen der Physik 265, 343–347 · doi:10.1002/andp.18862651010 · crossref ✓ 2026-09-19 · record
  2. [2]
    H. B. Callen. The application of Onsager's reciprocal relations to thermoelectric, thermomagnetic, and galvanomagnetic effects (1948)
    Physical Review 73, 1349 · doi:10.1103/PhysRev.73.1349 · crossref ✓ 2026-09-19 · record
  3. [3]
    H. J. Goldsmid. Introduction to Thermoelectricity (2nd ed.) (2016)
    Springer Series in Materials Science 121 · doi:10.1007/978-3-662-49256-7 · crossref ✓ 2026-09-19 · record
  4. [4]
    A. Bejan. Advanced Engineering Thermodynamics (4th ed.) (2016)
    Wiley · doi:10.1002/9781119245964 · crossref ✓ 2026-09-19 · record
  5. [5]
    C. Kittel. Introduction to Solid State Physics (8th ed.) (2005)
    Wiley · book, no DOI · record
  6. [6]
    C. Herring. Theory of the thermoelectric power of semiconductors (1954)
    Physical Review 96, 1163 · doi:10.1103/PhysRev.96.1163 · crossref ✓ 2026-09-19 · record
  7. [7]
    A. S. Yalamarthy et al.. Significant Phonon Drag Enables High Power Factor in the AlGaN/GaN Two-Dimensional Electron Gas (2019)
    Nano Letters 19, 3770–3776 · doi:10.1021/acs.nanolett.9b00901 · record
  8. [8]
    N. W. Ashcroft, N. D. Mermin. Solid State Physics (1976)
    Holt, Rinehart and Winston · book, no DOI · record

Cite this route

Physical Transformation Atlas (2026). route p-0a69862796: Electric potential difference → Ettingshausen effect → Temperature gradient → Heat conduction → Phonons → Phonon drag → Charge carriers → Electrical work. Dataset revision rbfbfcbb70e57 (hash of the canonical data). https://physical-transformation-atlas.wldud5192.workers.dev/path/0a69862796

Ids and matrix addresses are stable across revisions; the revision hash identifies the exact canonical files the record was compiled from and is meta.data_hash in every /api export. Reuse terms: see the license field in any export.