扭转双双层石墨烯中的亚稳态磁畴与反常面内磁场为0的电阻峰

中文摘要 AI 辅助

在石墨烯莫尔体系中，谷极化会产生轨道磁性，表现为反常霍尔效应，且当畴构型改变准粒子散射时，会导致纵向电阻出现巴克豪森跳变。然而，除了简单的极化畴图像外，畴内部及畴之间的自旋与谷结构，以及这些结构对输运的影响，人们还不甚了解。在扭转双双层石墨烯的谷极化四分之一金属态中，纵向电阻常出现一个尖锐且亚稳态的峰，位于零面内磁场处，其微观起源尚未明确。本文表明，该峰取决于轨道磁畴的构型，而该构型本身由进入有序态时的栅极电压轨迹以及该轨迹过程中存在的磁场（尤其是面内分量）决定。该效应对面内磁场分量的敏感性表明，通过自旋轨道耦合与谷极化关联的自旋，是畴形成和电阻峰中的关键自由度。

英文摘要

In graphene moirés, valley polarization gives rise to orbital magnetism, manifested as an anomalous Hall effect and resulting in Barkhausen jumps in longitudinal resistance when changing domain configurations modify quasiparticle scattering. Beyond a simple picture of polarized domains, however, spin and valley textures within and between the domains are less well understood, as is the effect of these textures on transport. In the valley-polarized quarter-metal state of twisted double bilayer graphene, a sharp and metastable peak in longitudinal resistance often appears at zero in-plane magnetic field, whose microscopic origin has yet to be identified. Here, we show that this peak depends on the configuration of domains of orbital magnetism, which is itself set by the gate-voltage trajectory used to enter the ordered state and by the magnetic field --- particularly the in-plane component --- present during that trajectory. The sensitivity of the effect to in-plane magnetic field components points to spin, linked to valley polarization through spin-orbit coupling, as the key degree of freedom in both the domain formation and the resistance peak.

发表机构

• University of British Columbia（不列颠哥伦比亚大学）
• Birla Institute of Technology and Science（比尔拉理工学院）

机构由 AI 辅助整理，请以论文原文为准。