近日，法国巴黎萨克雷大学的F. D. Parmentier及其研究团队取得一项新进展。经过不懈努力，他们观察到单层石墨烯中ν = 0量子霍尔铁磁体中消失不见的体热流。相关研究成果已于2024年10月29日在国际知名学术期刊《自然—物理学》上发表。

该研究团队观察到单层石墨烯在ν=0时体热传输消失，这与预期的基态相矛盾，因为即使在极低温度下，预期基态也应具有有限的热导率。这项研究结果强调了对ν=0性质进行进一步研究的必要性。

据悉，未掺杂的石墨烯是一种无带隙半导体；然而，当它被置于高垂直磁场中并冷却至低温时，会转变为绝缘态。这种状态被称为ν=0态，其成因是电子相互作用与n=0朗道能级形成的平带中的四重自旋和谷简并之间的相互作用。关于ν=0基态的性质，包括其自旋和谷极化，目前仍在研究讨论中。

附：英文原文

Title: Vanishing bulk heat flow in the ν = 0 quantum Hall ferromagnet in monolayer graphene

Author: Delagrange, R., Garg, M., Le Breton, G., Zhang, A., Dong, Q., Jin, Y., Watanabe, K., Taniguchi, T., Roulleau, P., Maillet, O., Roche, P., Parmentier, F. D.

Issue&Volume: 2024-10-29

Abstract: Undoped graphene is a gapless semiconductor; however, when placed under a high perpendicular magnetic field and cooled to low temperature, it develops an insulating state. This state, dubbed ν=0, is due to the interplay between electronic interactions and the four-fold spin and valley degeneracies in the flat band formed by the n=0 Landau level. The nature of the ground state of ν=0, including its spin and valley polarization, is still under debate. Here we observe vanishing bulk thermal transport in monolayer at ν=0, in contradiction with the expected ground state, which is predicted to have finite thermal conductance even at very low temperature. Our results highlight the need for further investigations on the nature of ν=0.

DOI: 10.1038/s41567-024-02672-0

Source: https://www.nature.com/articles/s41567-024-02672-0