Band structure mapping of bilayer graphene via quasiparticle scattering

Yankowitz, Matthew; Wang, Joel I-Jan; Li, Suchun; Birdwell, A. Glen; Chen, Yu-An; Watanabe, Kenji; Taniguchi, Takashi; Quek, Su Ying; Jarillo‐Herrero, Pablo; LeRoy, Brian J.

doi:10.1063/1.4890543

Cited by 25 publications

(28 citation statements)

References 28 publications

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“…consistent with our spectroscopic data. Additionally, we observed long-wavelength scattering waves in the lower graphene/hBN/NbSe2 area, similar to those observed in graphene near an atomic step edge [39,40] or near defects [41]. When imaging at higher voltage, VBias = 10 mV, both the vortices and the scattering waves are gone, as shown in Fig.…”

Section: Vortices In Graphene On Nbse2supporting

confidence: 74%

Local characterization and engineering of proximitized correlated states in graphene/NbSe2 vertical heterostructures

et al. 2020

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Using a van der Waals (vdW) vertical heterostructure consisting of monolayer graphene, monolayer hBN and NbSe2, we have performed local characterization of induced correlated states in different configurations. At a temperature of 4.6 K, we have shown that both superconductivity and charge density waves can be induced in graphene from NbSe2 by proximity effects. By applying a vertical magnetic field, we imaged the Abrikosov vortex lattice and extracted the coherence length for the proximitized superconducting graphene. We further show that the induced correlated states can be completely blocked by adding a monolayer hBN between the graphene and the NbSe2, which demonstrates the importance of the tunnel barrier and surface conditions between the normal metal and superconductor for the proximity effect.

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Section: Vortices In Graphene On Nbse2supporting

confidence: 74%

Local characterization and engineering of proximitized correlated states in graphene/NbSe2 vertical heterostructures

et al. 2020

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“…Throughout this work, we use the numerical values for the parameters listed in Ref. 19 consistent with previous experimental and theoretical investigations 23,24 . In momentum space, we distinguish between the two inequivalent Dirac points K and K and index them by ζ = ±1 following the convention ζ| K = +1 and ζ| K = −1.…”

Section: A the Non-interacting Single Particle Hamiltonianmentioning

confidence: 99%

Phase diagram of a graphene bilayer in the zero-energy Landau level

Knothe¹,

Jolicœur²

2016

Phys. Rev. B

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Bilayer graphene under a magnetic field has an octet of quasidegenerate levels due to spin, valley, and orbital degeneracies. This zero-energy Landau level is resolved into several incompressible states whose nature is still elusive. We use a Hartree-Fock treatment of a realistic tight-binding four-band model to understand the quantum ferromagnetism phenomena expected for integer fillings of the octet levels. We include the exchange interaction with filled Landau levels below the octet states. This Lamb-shift-like effect contributes to the orbital splitting of the octet. We give phase diagrams as a function of applied bias and magnetic field. Some of our findings are in agreement with experiments. We discuss the possible appearance of phases with orbital coherence.

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“…Several experimental works on free-standing BLG report an intrinsic (or spontaneous) band gap of ∆ int (T = 0) ≈ 1.5 meV vanishing above the critical temperature T crit ≈ 12 K [33][34][35]. To the contrary, no signatures of an intrinsic band gap are reported for BLG in van der Waals heterostructures (VDWHs) [36], in which thermoelectric properties may be significantly enhanced due to the suppression of out-of-plane (ZA) vibrations.…”

Section: Discussionmentioning

confidence: 99%

Thermoelectric properties of gapped bilayer graphene

Suszalski

Rut²,

Rycerz³

2019

J. Phys.: Condens. Matter

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Unlike in conventional semiconductors, both the chemical potential and the band gap in bilayer graphene (BLG) can be tuned via application of external electric field. Among numerous device implications, this property also designates BLG as a candidate for high-performance thermoelectric material. In this theoretical study we have calculated the Seebeck coefficients for abrupt interface separating weakly-and heavily-doped areas in BLG, and for a more realistic rectangular sample of mesoscopic size, contacted by two electrodes. For a given band gap (∆) and temperature (T ) the maximal Seebeck coefficient is close to the Goldsmid-Sharp value |S| GS max = ∆/(2eT ), the deviations can be approximated by the asymptotic expression |S| GS max −|S|max = (kB/e)× 1 2 ln u + ln 2 − 1 2 + O(u −1 ) , with the electron charge −e, the Boltzmann constant kB, and u = ∆/(2kBT ) 1. Surprisingly, the effects of trigonal warping term in the BLG low-energy Hamiltonian are clearly visible at few-Kelvin temperatures, for all accessible values of ∆ 300 meV. We also show that thermoelectric figure of merit is noticeably enhanced (ZT > 3) when a rigid substrate suppresses out-of-plane vibrations, reducing the contribution from ZA phonons to the thermal conductivity.with f BE (T, ω) = 1/ [ exp ( ω/k B T ) − 1 ] the Bose-Einstein distribution function and T ph (ω) the phononic transmission spectrum. We calculate T ph (ω) by adopting the procedure developed by Alofi and Srivastava [30] to the two systems considered in this work (see Supplementary Information, Sec. IV ).

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Band structure mapping of bilayer graphene via quasiparticle scattering

Cited by 25 publications

References 28 publications

Local characterization and engineering of proximitized correlated states in graphene/NbSe2 vertical heterostructures

Local characterization and engineering of proximitized correlated states in graphene/NbSe2 vertical heterostructures

Phase diagram of a graphene bilayer in the zero-energy Landau level

Thermoelectric properties of gapped bilayer graphene

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