论文标题
通过磁音 - phonon共振探测的悬浮石墨烯中的多体效应
Many-body effects in suspended graphene probed through magneto-phonon resonances
论文作者
论文摘要
我们利用微磁性拉曼散射光谱来探测悬浮的单层至Penta-layer石墨烯中的磁铁共振（MPR）。 MPR对应于避免区域中心光学声子（G模式）和光活性的Landau水平（LL）过渡之间的交叉，并提供了一种工具，以固定能量（$ \ \ \ \ rm {MEV} $）设置的固定能量（$ \ \ rm {MEV} $）。使用单粒子有效的双层模型，我们很容易提取与每个MPR相关的速度参数。单个速度参数略高于大量石墨值，足以适合所有MPR，适合$ n \ geq2 $ layer系统。相反，在单层石墨烯中，我们发现速度参数从$（1.23 \ pm 0.01）\ times 10^6〜 \ mathrm {m.s^{ - 1}} $最高$（1.45 \ pm0.02）\ times 10^6〜6〜 \ mathrm {m.s.s^$ 1} LL过渡夫妇到G模式声子。该结果被理解为在未经验证的石墨烯中增强多体效应的标志。
We make use of micro-magneto Raman scattering spectroscopy to probe magneto-phonon resonances (MPR) in suspended mono- to penta-layer graphene. MPR correspond to avoided crossings between zone-center optical phonons (G-mode) and optically-active inter Landau level (LL) transitions and provide a tool to perform LL spectroscopy at a fixed energy ($\approx 197~\rm{meV}$) set by the G-mode phonon. Using a single-particle effective bilayer model, we readily extract the velocity parameter associated with each MPR. A single velocity parameter slightly above the bulk graphite value suffices to fit all MPR for $N\geq2$ layer systems. In contrast, in monolayer graphene, we find that the velocity parameter increases significantly from $(1.23\pm 0.01) \times 10^6~\mathrm{m.s^{-1}}$ up to $(1.45\pm0.02) \times 10^6~\mathrm{m.s^{-1}}$ as the first to third optically-active inter LL transition couple to the G-mode phonon. This result is understood as a signature of enhanced many-body effects in unscreened graphene.
