Layer-controlled orbital-selective Mott transition in monolayer nickelate
Bibliographic record
Abstract
Dimensionality and electronic correlations are crucial elements of many quantum material properties. An example is the change of the electronic structure accompanied by the loss of quasiparticles when a metal is reduced from three dimensions to a lower dimension, where the Coulomb interaction between carriers becomes poorly screened. Here, using angle-resolved photoemission spectroscopy, we report an orbital-selective decoherence of spectral density in the perovskite nickelate <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mrow> <a:mi>LaNi</a:mi> <a:msub> <a:mi mathvariant="normal">O</a:mi> <a:mn>3</a:mn> </a:msub> </a:mrow> </a:math> toward the monolayer limit. The spectral weight of the <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"> <c:msub> <c:mi>d</c:mi> <c:mrow> <c:mi>z</c:mi> <c:mn>2</c:mn> </c:mrow> </c:msub> </c:math> band vanishes much faster than that of the <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"> <d:msub> <d:mi>d</d:mi> <d:mrow> <d:mi>x</d:mi> <d:mn>2</d:mn> <d:mo>−</d:mo> <d:mi>y</d:mi> <d:mn>2</d:mn> </d:mrow> </d:msub> </d:math> band as the thickness of the <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"> <e:mrow> <e:mi>LaNi</e:mi> <e:msub> <e:mi mathvariant="normal">O</e:mi> <e:mn>3</e:mn> </e:msub> </e:mrow> </e:math> layer is decreased to a single unit cell, indicating a stronger correlation effect for the former upon dimensional confinement. Dynamical mean-field theory calculations show an orbital-selective Mott transition largely due to the localization of <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"> <g:msub> <g:mi>d</g:mi> <g:mrow> <g:mi>z</g:mi> <g:mn>2</g:mn> </g:mrow> </g:msub> </g:math> electrons along the <h:math xmlns:h="http://www.w3.org/1998/Math/MathML"> <h:mi>c</h:mi> </h:math> axis in the monolayer limit. This orbital-selective correlation effect underpins many macroscopic properties of nickelates, such as metal-to-insulator transition and superconductivity, where most theories are built upon a <i:math xmlns:i="http://www.w3.org/1998/Math/MathML"> <i:mrow> <i:msub> <i:mi>d</i:mi> <i:mrow> <i:mi>x</i:mi> <i:mn>2</i:mn> <i:mo>−</i:mo> <i:mi>y</i:mi> <i:mn>2</i:mn> </i:mrow> </i:msub> <i:mtext>–</i:mtext> <i:msub> <i:mi>d</i:mi> <i:mrow> <i:mi>z</i:mi> <i:mn>2</i:mn> </i:mrow> </i:msub> </i:mrow> </i:math> two-band model.
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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 | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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 | 0.001 |
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".