Chern Insulators at Integer and Fractional Filling in Moiré Pentalayer Graphene
Bibliographic record
Abstract
The advent of moiré platforms for engineered quantum matter has led to discoveries of integer and fractional quantum anomalous Hall effects, with predictions for correlation-driven topological states based on electron crystallization. Here, we report an array of trivial and topological insulators formed in a moiré lattice of rhomobohedral pentalayer graphene (R5G). At a doping of one electron per moiré unit cell ( <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mi>ν</a:mi> <a:mo>=</a:mo> <a:mn>1</a:mn> </a:math> ), we see a correlated insulator with a Chern number that can be tuned between <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mi>C</c:mi> <c:mo>=</c:mo> <c:mn>0</c:mn> </c:math> and <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mo>+</e:mo> <e:mn>1</e:mn> </e:math> by an electric displacement field. This is accompanied by a series of additional Chern insulators with <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:mi>C</g:mi> <g:mo>=</g:mo> <g:mo>+</g:mo> <g:mn>1</g:mn> </g:math> originating from fractional fillings of the moiré lattice— <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"> <i:mi>ν</i:mi> <i:mo>=</i:mo> <i:mn>1</i:mn> <i:mo>/</i:mo> <i:mn>4</i:mn> </i:math> , <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"> <k:mn>1</k:mn> <k:mo>/</k:mo> <k:mn>3</k:mn> </k:math> , and <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"> <m:mn>2</m:mn> <m:mo>/</m:mo> <m:mn>3</m:mn> </m:math> —associated with the formation of moiré-driven topological electronic crystals. At <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline"> <o:mi>ν</o:mi> <o:mo>=</o:mo> <o:mn>2</o:mn> <o:mo>/</o:mo> <o:mn>3</o:mn> </o:math> the system exhibits an integer quantum anomalous Hall effect at zero magnetic field, but further develops hints of an incipient <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"> <q:mi>C</q:mi> <q:mo>=</q:mo> <q:mn>2</q:mn> <q:mo>/</q:mo> <q:mn>3</q:mn> </q:math> fractional Chern insulator in a modest field. Our results establish moiré R5G as a fertile platform for studying the competition and potential intertwining of integer and fractional Chern insulators.
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 | 0.000 |
| 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".