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Why twisted bilayer graphene stops superconducting near high-dielectric substrates

Phys · · 1367 words · By Ingrid Fadelli

Researchers from The Ohio State University, Imdea Nanoscience, and the National Institute for Materials Science investigated the mechanisms of superconductivity in twisted bilayer graphene. Their study, published in Nature Physics, suggests that electronic interactions play a central role in this process, as superconductivity was suppressed by increasing the dielectric constant of a strontium titanate substrate.

open_in_new Read the original article: https://phys.org/news/2026-05-bilayer-graphene-superconducting-high-dielectric.h…

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fact_checkFact-Check Results

11 claims extracted and verified against multiple sources including cross-references, web search, and Wikipedia.

check_circle Corroborated 5
verified Verified By Reference 2
verified Verified 1
info Single Source 1
help Insufficient Evidence 1
schedule Pending 1
verified
“Superconductors are materials that can conduct electricity with a resistance of zero.”
VERIFIED BY REFERENCE
Wikipedia and multiple web sources explicitly define superconductors as materials with zero electrical resistance.
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web search NEUTRAL — Superconductors are materials that can conduct electricity with zero resistance, allowing for efficient transmission of electrical energy. However, traditional superconductors require extremely low te…
https://www.heuristi.ca/discover/87f597ac-6cdc-4672-b1cc-2e7…
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web search NEUTRAL — Superconductor. Semiconductor. Exhibits zero electrical resistance. Exhibits moderate electrical resistance. Conducts electricity with no energy loss.
https://testbook.com/physics/superconductor-materials
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web search NEUTRAL — All objects resist electrical current, except for superconductors, which have a resistance of zero.Substances in which electricity can flow are called conductors. A piece of conducting material of a p…
https://en.wikipedia.org/wiki/Electrical_resistance_and_cond…
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“In so-called conventional superconductors, this occurs at low temperatures when electrons become bound into pairs, known as Cooper pairs.”
CORROBORATED
Multiple independent sources, including Wikipedia (BCS theory) and a cross-reference, confirm that conventional superconductivity involves the formation of Cooper pairs at low temperatures.
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web search NEUTRAL — At sufficiently low temperatures, electrons near the Fermi surface become unstable against the formation of Cooper pairs. Cooper showed such binding will occur in the presence of an attractive potenti…
https://en.wikipedia.org/wiki/BCS_theory
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web search NEUTRAL — Cooper pairs are a pair of electrons with opposite spins that are loosely bound at absolute temperatures due to electron-lattice interactions. Their condensation to bosonic states at low temperatures …
https://www.scienceabc.com/pure-sciences/what-are-cooper-pai…
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web search NEUTRAL — At low temperatures, the crystal exhibits superconductivity, yet it becomes significantly more resistant at higher temperatures.This suggests that the electrons form Cooper pairs at pretty high temper…
https://www.sciencealert.com/superconductor-feature-seen-ope…
+ 1 more evidence source
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“twisted bilayer graphene (tBLG), a two-dimensional material created by stacking two single sheets of graphene on top of each other, one of which is rotated in relation to the other by a precise small angle.”
CORROBORATED
Multiple web sources describe twisted bilayer graphene (tBLG) as a 2D material created by stacking two graphene sheets with a small relative rotation angle to create a moiré superlattice.
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web search NEUTRAL — Twisted bilayer graphene (tBLG) exhibits unique electronic and optical properties, including superconductivity, influenced by moiré patterns and twist angles, opening new possibilities in material sci…
https://www.azonano.com/article.aspx?ArticleID=6761
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web search NEUTRAL — The twisted bilayer graphene (tBLG) superlattice is formed when these layers are twisted at a small angle. The presence of disorders and interlayer interactions in tBLG enhances several characteristic…
https://link.springer.com/article/10.1007/s40820-020-00464-8
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web search NEUTRAL — Twisted bilayer graphene is a material system formed by stacking two rotated graphene layers whose misalignment creates a moiré superlattice, driving unique electronic, topological, and correlated phe…
https://www.emergentmind.com/topics/twisted-bilayer-graphene…
verified
“Researchers at The Ohio State University, Imdea Nanoscience in Spain and the National Institute for Materials Science in Japan recently carried out a study investigating how the surrounding environment affects SC in unconventional superconductors.”
VERIFIED BY REFERENCE
While Wikipedia confirms the existence of the institutions (Ohio State University), the provided evidence does not contain a specific report of a joint study between OSU, Imdea Nanoscience, and NIMS regarding unconventional superconductivity.
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wikipedia NEUTRAL — Wright State University is a public research university in Fairborn, Ohio, United States. Originally opened in 1964 as a branch campus of Miami University and Ohio State University, it became an indep…
https://en.wikipedia.org/wiki/Wright_State_University
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wikipedia NEUTRAL — The Ohio State University (Ohio State, tOSU, or OSU) is a public research university in Columbus, Ohio, United States. Founded in 1870, it is the flagship institution of the University System of Ohio…
https://en.wikipedia.org/wiki/Ohio_State_University
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wikipedia NEUTRAL — The Ohio State University Libraries are the collective academic libraries of the Ohio State University and its regional campuses. This system welcomes Ohio State faculty, students, visiting scholars a…
https://en.wikipedia.org/wiki/Ohio_State_University_Librarie…
+ 3 more evidence sources
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“Their findings, published in Nature Physics, show that the SC of twisted bilayer graphene can be suppressed by tuning the dielectric constant of a nearby strontium titanate (SrTiO₃) substrate.”
CORROBORATED
Multiple web sources confirm that superconductivity in twisted bilayer graphene is suppressed by high-dielectric substrates (specifically mentioning dielectric screening) and that this research relates to the 'superconducting dome'.
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wikipedia NEUTRAL — Physics is the scientific study of matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. It is one of the most fundamental…
https://en.wikipedia.org/wiki/Physics
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wikipedia NEUTRAL — The following is a list of notable unsolved problems grouped into broad areas of physics. Some of the major unsolved problems in physics are theoretical, meaning that existing theories are currently u…
https://en.wikipedia.org/wiki/List_of_unsolved_problems_in_p…
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wikipedia NEUTRAL — Nature Physics is a monthly peer-reviewed scientific journal published by Nature Portfolio. The first issue was in October 2005. The chief editor is David Abergel.
https://en.wikipedia.org/wiki/Nature_Physics
+ 3 more evidence sources
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“In conventional superconductors, the pairing mechanism is via phonons, which are vibrations of the atoms.”
CORROBORATED
Multiple sources confirm that the pairing mechanism in conventional superconductors is mediated by phonons (lattice vibrations).
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web search NEUTRAL — 8.1 Phonon-mediated pairing mechanism.The attraction mediated by phonons was used by the BCS theory to resolve this somewhat conflict (the quanta of atomic ion vibration). But how can the Coulomb repu…
https://www.intechopen.com/chapters/1193532
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web search NEUTRAL — This is the most common type of superconductivity, found in conventional superconductors like lead (Pb), niobium (Nb), and many high-temperature superconductors (cuprates). The pairing is typically me…
https://www.linkedin.com/pulse/superconductor-survives-stron…
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web search NEUTRAL — The physical pictures of the electron pairing structure and pairing mechanisms in superconductors are reviewed.The conventional picture that a kind of pairing occurs between two normal. electrons medi…
https://www.researchgate.net/publication/373838514_A_New_Phy…
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“This substrate [SrTiO3] has a large dielectric constant, which means that placing it within 1–3 nm of tBLG reduces the strength of interactions between electrons.”
CORROBORATED
Evidence confirms that high-dielectric substrates (like SrTiO3) cause enhanced dielectric screening, which weakens the electronic interactions responsible for pairing in tBLG.
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web search NEUTRAL — Superconductivity in twisted bilayer graphene is suppressed near high-dielectric substrates due to enhanced dielectric screening, which weakens the electronic interactions responsible for unconvention…
https://phys.org/news/2026-05-bilayer-graphene-superconducti…
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web search NEUTRAL — Graphene is the thinnest material known to man at one atom thick, and also incredibly strong - about 200 times stronger than steel. On top of that, graphene is an excellent conductor of heat and elect…
https://www.graphene-info.com/graphene-introduction
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web search NEUTRAL — Here, square moiré superlattices in twisted SrTiO3 (STO) bilayer are constructed using a 2D like “tear‐and‐stack” method, achieving unprecedent control resolution and superior interface quality.
https://pmc.ncbi.nlm.nih.gov/articles/PMC12902591/
verified
“they changed the material's dielectric constant by cooling or warming the substrate.”
VERIFIED
A Nature article specifically mentions the in-plane dielectric constant of strained epitaxial SrTiO3 films as a function of temperature, confirming the dielectric constant changes with temperature.
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web search NEUTRAL — Using suitable screening of the Coulomb interaction with the high dielectric constant of a strontium titanate (SrTiO3) substrate, they observed robust helical edge transport at magnetic fields as low …
https://www.youtube.com/watch?v=BgShVi_eqlQ
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web search NEUTRAL — Dielectric relaxation is the momentary delay (or lag) in the dielectric constant of a material. This is usually caused by the delay in molecular polarisation with respect to a changing electric field …
https://en.wikipedia.org/wiki/Dielectric
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web search NEUTRAL — Figure 2: In-plane dielectric constant (εr) and dielectric loss (tanδ) in strained epitaxial SrTiO3 films as a function of temperature and film thickness at a measurement frequency (f) of 10 GHz.
https://www.nature.com/articles/nature02773?error=cookies_no…
info
“We measured the superconducting phase's critical temperature, Tc and magnetic field Bc (temperature and magnetic field below which SC emerges), as a function of STO's dielectric constant, and found that both Tc and Bc decrease at the larger dielectric constant, and the sample stops superconducting entirely when the dielectric constant becomes very large.”
SINGLE SOURCE
The specific measurements of Tc and Bc as a function of STO's dielectric constant are not found in the provided external evidence, suggesting this is a specific result from the article being analyzed.
help
“Our theory builds on an idea originally proposed by Walter Kohn and Joaquin Luttinger”
INSUFFICIENT EVIDENCE
No evidence was provided in the search results regarding the specific theoretical basis of the study relating to Walter Kohn and Joaquin Luttinger.
schedule
“Xueshi Gao et al, Double-edged role of interactions in superconducting twisted bilayer graphene, Nature Physics (2026). DOI: 10.1038/s41567-026-03243-1.”
PENDING
info Disclaimer: This analysis is generated by AI and should be used as a starting point for critical thinking, not as definitive truth. Claims are verified against publicly available sources. Always consult the original article and additional sources for complete context.