Ravi Kumar, Saurabh Kumar Srivastav, Ujjal Roy, Ujjawal Singhal, K. Watanabe, T. Taniguchi, Vibhor Singh, P. Roulleau, Anindya Das
{"title":"Absence of heat flow in ν = 0 quantum Hall ferromagnet in bilayer graphene","authors":"Ravi Kumar, Saurabh Kumar Srivastav, Ujjal Roy, Ujjawal Singhal, K. Watanabe, T. Taniguchi, Vibhor Singh, P. Roulleau, Anindya Das","doi":"10.1038/s41567-024-02673-z","DOIUrl":null,"url":null,"abstract":"The charge neutrality point of bilayer graphene, denoted as the ν = 0 state, manifests competing phases marked by spontaneous ordering of the spin, valley and layer degrees of freedom under external magnetic and electric fields. However, due to their electrically insulating nature, identifying these phases through electrical conductance measurements is a challenge. A recent theoretical proposal suggests that thermal transport measurements can detect these competing phases. Here we experimentally show that the bulk thermal transport of the ν = 0 state in bilayer graphene vanishes. This is in contrast to the theory, which predicts a finite thermal conductance in the ν = 0 state. By varying the external electric field and conducting temperature-dependent measurements, our results suggest that there are gapped collective excitations in the ν = 0 state. Our findings underscore the necessity for further investigations into the nature of the ν = 0 state. The ground state of charge-neutral bilayer graphene in a strong magnetic field is not fully determined. Now thermal transport measurements show an absence of heat flow through that state, suggesting that its collective excitations could be gapped.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 12","pages":"1941-1947"},"PeriodicalIF":17.6000,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nature Physics","FirstCategoryId":"101","ListUrlMain":"https://www.nature.com/articles/s41567-024-02673-z","RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"PHYSICS, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
The charge neutrality point of bilayer graphene, denoted as the ν = 0 state, manifests competing phases marked by spontaneous ordering of the spin, valley and layer degrees of freedom under external magnetic and electric fields. However, due to their electrically insulating nature, identifying these phases through electrical conductance measurements is a challenge. A recent theoretical proposal suggests that thermal transport measurements can detect these competing phases. Here we experimentally show that the bulk thermal transport of the ν = 0 state in bilayer graphene vanishes. This is in contrast to the theory, which predicts a finite thermal conductance in the ν = 0 state. By varying the external electric field and conducting temperature-dependent measurements, our results suggest that there are gapped collective excitations in the ν = 0 state. Our findings underscore the necessity for further investigations into the nature of the ν = 0 state. The ground state of charge-neutral bilayer graphene in a strong magnetic field is not fully determined. Now thermal transport measurements show an absence of heat flow through that state, suggesting that its collective excitations could be gapped.
期刊介绍:
Nature Physics is dedicated to publishing top-tier original research in physics with a fair and rigorous review process. It provides high visibility and access to a broad readership, maintaining high standards in copy editing and production, ensuring rapid publication, and maintaining independence from academic societies and other vested interests.
The journal presents two main research paper formats: Letters and Articles. Alongside primary research, Nature Physics serves as a central source for valuable information within the physics community through Review Articles, News & Views, Research Highlights covering crucial developments across the physics literature, Commentaries, Book Reviews, and Correspondence.