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arXiv 1904.04425cond-mat.mtrl-scicond-mat.mes-hall
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石墨烯中巨量子化声子模的Tunnel谱观测

Observation of Giant Quantized Phonon Modes in Graphene via Tunneling Spectra

Yu Zhang, Qian Yang, Lin He

摘要:

声子是晶格的基本振动模式,通过电子-声子相互作用在决定材料的电子性质方面起着至关重要的作用。然而,在电学测量中,直接探测材料的声子模式已被证明是困难的。本文报道了在磁场作用下,利用隧道谱观测石墨烯单层中K和K离面声子的巨量子化声子峰,这种方法通常被用来测量材料的局域电子性质.垂直的磁场将石墨烯中的无质量狄拉克费米子量子化为离散的朗道能级(LL)。我们证明了准粒子的声子在石墨烯的发光层中的发射或吸收产生了一个新的离散态序列:量子化声子模。在我们的隧穿谱中,由于K和K面外声子打开了一个非弹性隧穿通道,所观察到的声子峰的强度大约是LL的50倍。我们还表明,它是可能的开关量子声子模式在纳米尺度上通过控制石墨烯和支撑衬底之间的相互作用。

英文摘要:

Phonons, the fundamental vibrational modes of a crystal lattice, play a crucial role in determining electronic properties of materials through electron-phonon interaction. However, it has proved difficult to directly probe the phonon modes of materials in electrical measurements. Here, we report the observation of giant quantized phonon peaks of the K and K out-of-plane phonon in graphene monolayer in magnetic fields via tunneling spectra, which are usually used to measure local electronic properties of materials. A perpendicular magnetic field quantizes massless Dirac fermions in graphene into discrete Landau levels (LLs). We demonstrate that emission or absorption of phonons of quasiparticles in the LLs of graphene generates a new sequence of discrete states: the quantized phonon modes. In our tunneling spectra, the intensity of the observed phonon peaks is about 50 times larger than that of the LLs because that the K and K out-of-plane phonon opens an inelastic tunneling channel. We also show that it is possible to switch on off the quantized phonon modes at nanoscale by controlling interactions between graphene and the supporting substrate.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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