Electronic Band Structure of a Superconducting Nickelate Probed by the Seebeck Coefficient in the Disordered Limit
Bibliographic record
Abstract
Superconducting nickelates are a new family of strongly correlated electron materials with a phase diagram closely resembling that of superconducting cuprates. While analogy with the cuprates is natural, very little is known about the metallic state of the nickelates, making these comparisons difficult. We probe the electronic dispersion of thin-film superconducting five-layer ( <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mi>n</a:mi> <a:mo>=</a:mo> <a:mn>5</a:mn> </a:math> ) and metallic three-layer ( <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mi>n</c:mi> <c:mo>=</c:mo> <c:mn>3</c:mn> </c:math> ) nickelates by measuring the Seebeck coefficient <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mi>S</e:mi> </e:math> . We find a temperature-independent and negative <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:mi>S</g:mi> <g:mo>/</g:mo> <g:mi>T</g:mi> </g:math> for both <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"> <i:mi>n</i:mi> <i:mo>=</i:mo> <i:mn>5</i:mn> </i:math> and <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"> <k:mi>n</k:mi> <k:mo>=</k:mo> <k:mn>3</k:mn> </k:math> nickelates. These results are in stark contrast to the strongly temperature-dependent <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"> <m:mi>S</m:mi> <m:mo>/</m:mo> <m:mi>T</m:mi> </m:math> measured at similar electron filling in the cuprate <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline"> <o:mrow> <o:msub> <o:mrow> <o:mi>La</o:mi> </o:mrow> <o:mrow> <o:mn>1.36</o:mn> </o:mrow> </o:msub> </o:mrow> <o:mrow> <o:msub> <o:mrow> <o:mi>Nd</o:mi> </o:mrow> <o:mrow> <o:mn>0.4</o:mn> </o:mrow> </o:msub> </o:mrow> <o:mrow> <o:msub> <o:mrow> <o:mi>Sr</o:mi> </o:mrow> <o:mrow> <o:mn>0.24</o:mn> </o:mrow> </o:msub> </o:mrow> <o:mrow> <o:msub> <o:mrow> <o:mi>CuO</o:mi> </o:mrow> <o:mrow> <o:mn>4</o:mn> </o:mrow> </o:msub> </o:mrow> </o:math> . The electronic structure calculated from density-functional theory can reproduce the temperature dependence, sign, and amplitude of <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"> <q:mi>S</q:mi> <q:mo>/</q:mo> <q:mi>T</q:mi> </q:math> in the nickelates using Boltzmann transport theory. This demonstrates that the electronic structure obtained from first-principles calculations provides a reliable description of the fermiology of superconducting nickelates and suggests that, despite indications of strong electronic correlations, there are well-defined quasiparticles in the metallic state. Finally, we explain the differences in the Seebeck coefficient between nickelates and cuprates as originating in strong dissimilarities in impurity concentrations. Our study demonstrates that the high elastic scattering limit of the Seebeck coefficient reflects only the underlying band structure of a metal, analogous to the high magnetic field limit of the Hall coefficient. This opens a new avenue for Seebeck measurements to probe the electronic band structures of relatively disordered quantum materials. Published by the American Physical Society 2024
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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".