Ingrid Fadelli is a writer for Phys.org.
Physicists and material scientists have found new ways to study correlated phases of matter, such as superconductivity and the correlated insulator phase. A research team at the Massachusetts institute of Technology discovered magic-angle twisted trilayer graphene, a superconductor. The material consists of three sheets of Graphene stacked together.
If it were a conventional superconductor, magic-angle twisted trilayer graphene would exhibit superconductivity much lower than it does now. The underpinning physics of this material is not fully understood.
Researchers at Brown University are studying superconductivity in twisted trilayer graphene. The paper introduces constraints that could affect the models of superconductivity.
A few previous experiments showed that the phase of magic-angle twisted trilayer graphene can survive a large external magnetic field that violates the Pauli limit, where electron pairs with opposite spin orientations are expected to be destroyed.
The goal of the recent work by Li and his colleagues at Brown University was to better understand the unusual superconducting behavior observed in magic-angle twisted trilayer graphene. Coloumb screening is a technique that allows scientists to investigate the role of Coulomb interactions in stabilizing the superconducting phase. New findings enriched the current understanding of the mechanism underlying superconductivity in the promising new material.
Last year, we demonstrated that one can directly manipulate the strength of the Coulomb interaction using a specially designed 2D material hetersotructure. We showed that weaker Coulomb interaction strengthens superconductivity.
The screening technique used by Li and his colleagues was revealed in one of their previous studies. A pioneer in the study of 2D material structures with complex design is a post-doctoral researcher at Brown University.
The screening measurement we collected in twisted trilayer graphene shows similar results to the measurement performed on magic-angle graphene bilayer, which suggests that the phases in these two systems have a common origin.
The new insight offered by the findings greatly improves the understanding of superconductivity in twisted graphene structures. In the future, the team plans to investigate this structure further and use the same technique they used to examine other materials.
The behavior we observed provides strong support for a group of theoretical models. We plan on applying the same technique to learn more about 2D materials.
More information: Xiaoxue Liu et al, Isospin order in superconducting magic-angle twisted trilayer graphene, Nature Physics (2022). DOI: 10.1038/s41567-022-01515-0 Journal information: Nature PhysicsThe Science X Network will be launched in 2022.
Citation: Study improves the understanding of superconductivity in magic-angle twisted trilayer graphene (2022, March 29) retrieved 29 March 2022 from https://phys.org/news/2022-03-superconductivity-magic-angle-trilayer-graphene.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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