Observation of logarithmic Kohn anomaly in monolayer graphene

Zhao, Yanchong; Du, Luojun; Yang, Wei; Shen, Cheng; Tang, Jian; Li, Xiaomei; Chu, Yanbang; Tian, Jinpeng; Watanabe, Kenji; Taniguchi, Takashi; Yang, Rong; Shi, Dongxia; Sun, Zhipei; Zhang, Guangyu

doi:10.1103/physrevb.102.165415

Cited by 8 publications

(6 citation statements)

References 66 publications

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“…High-quality, hexagonal boron nitride (h-BN)encapsulated bilayer MoS 2 devices with two symmetric graphene gates, as illustrated in Fig. 1(a), were fabricated using the layer-by-layer dry transfer technique [39][40][41]. Three h-BN-encapsulated bilayer MoS 2 devices (labeled as D1, D2, and D3) were studied and show consistent results.…”

mentioning

confidence: 89%

Interlayer exciton complexes in bilayer MoS2

Zhao

Yang

et al. 2022

Phys. Rev. B

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confidence: 89%

Interlayer exciton complexes in bilayer MoS2

Zhao

Yang

et al. 2022

Phys. Rev. B

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“…It is important to note that Raman probes the local doping and that a shift of the G peak to larger wavenumbers occurs for electron‐doping and hole‐doping. [ 45,46 ] Transport measurements instead probe the average net charging by a shift of the Dirac voltage. The formation of electron–hole puddles with zero net charges, as reported in the absence of charged impurities, [ 47 ] could explain the observation with methanol, and their presence would reduce the carrier mobility and increase the residual carrier concentration without shifting the Dirac voltage.…”

Section: Resultsmentioning

confidence: 99%

Sensing Molecules with Metal–Organic Framework Functionalized Graphene Transistors

et al. 2021

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Graphene is inherently sensitive to vicinal dielectrics and local charge distributions, a property that can be probed by the position of the Dirac point in graphene field‐effect transistors. Exploiting this as a useful sensing principle requires selectivity; however, graphene itself exhibits no molecule‐specific interaction. Complementarily, metal–organic frameworks can be tailored to selective adsorption of specific molecular species. Here, a selective ethanol sensor is demonstrated by growing a surface‐mounted metal–organic framework (SURMOF) directly onto graphene field‐effect transistors (GFETs). Unprecedented shifts of the Dirac point, as large as 15 V, are observed when the SURMOF/GFET is exposed to ethanol, while a vanishingly small response is observed for isopropanol, methanol, and other constituents of the air, including water. The synthesis and conditioning of the hybrid materials sensor with its functional characteristics are described and a model is proposed to explain the origin, magnitude, and direction of the Dirac point voltage shift. Tailoring multiple SURMOFs to adsorb specific gases on an array of such devices thus generates a versatile, selective, and highly sensitive platform for sensing applications.

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“…In addition, due to the presence of the Dirac point in graphene which behaves as the Fermi surface, the electron-phonon coupling effect similar to Kohn anaomaly in the phonon dispersion curves [52,53] can take place. For instance, let us mention the observation of this phenomenon in the optical [54,55] and acoustical [56] dispersion curves of graphene under strain. In addition, Kohn anomalies have been measured in Nitride-based 6 nm-6 nm metal-semiconductor (HfN-ScN) SL using inelastic x-ray scattering [57].…”

Section: Discussionmentioning

confidence: 99%

Graphene-Based One-Dimensional Terahertz Phononic Crystal: Band Structures and Surface Modes

Quotane¹,

Boudouti²,

Djafari‐Rouhani

2020

Nanomaterials

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In this paper, we provide a theoretical and numerical study of the acoustic properties of infinite and semi-infinite superlattices made out of graphene-semiconductor bilayers. In addition to the band structure, we emphasize the existence and behavior of localized and resonant acoustic modes associated with the free surface of such structures. These modes are polarized in the sagittal plane, defined by the incident wavevector and the normal to the layers. The surface modes are obtained from the peaks of the density of states, either inside the bulk bands or inside the minigaps of the superlattice. In these structures, the two directions of vibrations (longitudinal and transverse) are coupled giving rise to two bulk bands associated with the two polarizations of the waves. The creation of the free surface of the superlattice induces true surface localized modes inside the terahertz acoustic forbidden gaps, but also pseudo-surface modes which appear as well-defined resonances inside the allowed bands of the superlattice. Despite the low thickness of the graphene layer, and though graphene is a gapless material, when it is inserted periodically in a semiconductor, it allows the opening of wide gaps for all values of the wave vector k// (parallel to the interfaces). Numerical illustrations of the band structures and surface modes are given for graphene-Si superlattices, and the surface layer can be either Si or graphene. These surface acoustic modes can be used to realize liquid or bio-sensors graphene-based phononic crystal operating in the THz frequency domain.

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Observation of logarithmic Kohn anomaly in monolayer graphene

Cited by 8 publications

References 66 publications

Interlayer exciton complexes in bilayer MoS2

Interlayer exciton complexes in bilayer MoS2

Sensing Molecules with Metal–Organic Framework Functionalized Graphene Transistors

Graphene-Based One-Dimensional Terahertz Phononic Crystal: Band Structures and Surface Modes

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