AI 中文总结
研究量子霍尔体系中库仑相互作用对临界性的影响，通过结合温度与电流标度及双石墨门控石墨烯器件，分别提取动力学指数z和局域长度指数γ，揭示屏蔽对它们的不同影响，确立几何屏蔽为控制相互作用和区分效应的通用工具。
AI 中文摘要
在连续电子相变中，库仑相互作用会改变长度、能量和温度之间的关系，但实验上区分其对空间与动力学临界性的影响一直很困难，因为仅有限温度标度测量的只是组合指数κ = 1/(zγ)。本文介绍了两项进展来解决这一限制。一是结合温度标度与独立电流标度，在量子霍尔平台转变处分别提取动力学指数z和局域长度指数γ。二是利用双石墨门控石墨烯器件，通过磁长度lB与石墨门距离d的比值几何调节有效库仑相互作用范围，在同一器件平台上跟踪屏蔽和非屏蔽相互作用区域的这种分离。温度标度给出屏蔽区域κ≈0.21，非屏蔽区域κ≈0.41；结合电流标度表明屏蔽使z从非屏蔽区域的≈1变为屏蔽区域的≈2，而γ始终接近2.4。结果表明门控屏蔽选择性地改变了量子霍尔转变中依赖相互作用的动力学部分，在实验不确定性范围内局域长度指数γ不变。更广泛地说，这项工作确立了几何屏蔽作为控制相互作用以及区分相关二维系统中相互作用和无序效应的通用工具，包括分数量子霍尔态、莫尔材料和其他强局域电子相。
英文摘要
At continuous electronic phase transitions, Coulomb interactions can modify the relation between length, energy, and temperature, but experimentally disentangling their effects on spatial versus dynamical criticality has remained difficult, since finite-temperature scaling alone measures only the combined exponent $κ= 1/(zγ)$. Here, we introduce two advances that resolve this limitation. First, by combining temperature scaling with independent current scaling, we separately extract the dynamical exponent $z$ and the localization-length exponent $γ$ at the quantum Hall plateau transition -- rather than inferring one from an assumed value of the other. Second, using dual-graphite-gated graphene devices in which the effective Coulomb interaction range is tuned geometrically by the ratio of the magnetic length $l_B$ to the graphite-gate distance $d$, we track this separation across both screened and unscreened interaction regimes within the same device platform. Temperature scaling gives $κ\simeq 0.21$ in the screened regime and $κ\simeq 0.41$ in the unscreened regime; combining this with current scaling reveals that screening changes $z$ from $\simeq 1$ in the unscreened regime to $\simeq 2$ in the screened regime. In contrast, $γ$ remains close to $2.4$ throughout. Our results establish that gate-controlled screening selectively modifies the interaction-dependent dynamical sector of the quantum Hall transition, leaving the localization-length exponent $γ$ unchanged within experimental uncertainty. More broadly, this work establishes geometric screening as a versatile tool for controlling interactions and disentangling interaction and disorder effects in correlated two-dimensional systems, including fractional quantum Hall states, moiré materials, and other strongly localized electronic phases.
Comments22 pages
