Unveiling the nature of atomic defects in graphene on a metal surface

• Karl Rothe,
• Nicolas Néel and
• Jörg Kröger

Beilstein J. Nanotechnol. 2024, 15, 416–425, doi:10.3762/bjnano.15.37

• presence of graphene [48]. The -shaped feature with minimum signal slightly below zero bias may be associated with the Dirac cone at the BZ -point. Figure 1d reveals the spatial evolution of the spectra, which shows a gradual quenching of the Ir(111) surface resonance signal accompanied by a small shift

• toward zero bias voltage upon laterally approaching the defect center. The Dirac cone signal shifts from ≈18 mV above undistorted graphene (top spectrum in Figure 1d) to ≈−40 mV atop the center of the defect. While the extracted energy of the Dirac point is in agreement with previously reported values

• substrate d bands. This scenario would explain the shift of the Dirac cone signature in dI/dV spectra from positive sample voltages for intact graphene to negative voltages atop the defect (Figure 1d). While intact graphene on Ir(111) is slightly p-doped and exhibits the Dirac cone at energies above EF [52

Nonequilibrium Kondo effect in a graphene-coupled quantum dot in the presence of a magnetic field

• Levente Máthé and
• Ioan Grosu

Beilstein J. Nanotechnol. 2020, 11, 225–239, doi:10.3762/bjnano.11.17

• points the energy dispersion of quasiparticles in graphene is linear in momentum. This linear band structure is called a Dirac cone, and it is at the basis of many interesting physical phenomena such as the ’chiral’ quantum Hall effect [51], the Klein tunneling effect [50] and the Aharonov–Bohm effect

Metal-free catalysis based on nitrogen-doped carbon nanomaterials: a photoelectron spectroscopy point of view

• Mattia Scardamaglia and
• Carla Bittencourt

Beilstein J. Nanotechnol. 2018, 9, 2015–2031, doi:10.3762/bjnano.9.191

• , several strategies have been employed to tailor the properties of graphene. Being very sensitive to local perturbations, any modification of the lattice or adsorption of foreign atoms or molecules produce sudden evident changes in the density of states that can be monitored by the shift of the Dirac cone

• graphitic N. Both effects were reported to be responsible for the increase in the DOS. In graphene, the modification of the DOS is reflected in a shift of the Dirac cone, as confirmed experimentally recently by changing the ratio between graphitic N and pyridinic N through thermal treatments [57] and by the

Robust midgap states in band-inverted junctions under electric and magnetic fields

• Álvaro Díaz-Fernández,
• Natalia del Valle and
• Francisco Domínguez-Adame

Beilstein J. Nanotechnol. 2018, 9, 1405–1413, doi:10.3762/bjnano.9.133

• . A two-band model within the envelope-function approximation predicts the appearance of midgap interface states with Dirac cone dispersions in band-inverted junctions, namely, when the gap changes sign along the growth direction. We present a thorough study of these interface electron states in the

• presence of crossed electric and magnetic fields, the electric field being applied along the growth direction of a band-inverted junction. We show that the Dirac cone is robust and persists even if the fields are strong. In addition, we point out that Landau levels of electron states lying in the

• the case of topological crystalline insulators from the fact that a magnetic field perpendicular to a mirror plane renders a system that is still symmetric about that plane [8]. This is not the case in a magnetic field parallel to the mirror plane, where the Dirac cone turns into the usual

Predicting the strain-mediated topological phase transition in 3D cubic ThTaN₃

• Chunmei Zhang and
• Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1399–1404, doi:10.3762/bjnano.9.132

• 1 eV, but its electronic properties remain largely unexplored. By using density functional theory, we find that the band gap of ThTaN3 is very sensitive to the hydrostatic pressure/strain. A Dirac cone can emerge around the Γ point with an ultrahigh Fermi velocity at a compressive strain of 8

• the d-orbital of the heavy element Ta and the p-orbital of N. Our results highlight a new 3D topological insulator with strain-mediated topological transition for potential applications in future spintronics. Keywords: Dirac cone; strain; ThTaN3; topological insulator; Introduction The ThTaN3

• pressure/strain. A Dirac cone can emerge in the ThTaN3 compound with an ultrahigh Fermi velocity under an 8% compressive strain. The band gap opening, induced by SOC, can be as high as 0.25 eV, which is large enough for the realization of the quantum spin Hall (QSH) states at room temperature. In addition

An implementation of spin–orbit coupling for band structure calculations with Gaussian basis sets: Two-dimensional topological crystals of Sb and Bi

• Sahar Pakdel,
• Mahdi Pourfath and
• J. J. Palacios

Beilstein J. Nanotechnol. 2018, 9, 1015–1023, doi:10.3762/bjnano.9.94

• are decoupled and the gap at the Dirac point closes down, the Fermi energy crosses the Dirac cone above the Dirac point, but also crosses 6 surface state pockets and 3 bulk pockets (see, e.g., [51]). It has been shown that multilayer antimonene with hexagonal structure, prefers ABC stacking and is

• surface Dirac cone states around the Γ point and of the states in the nearby pockets, comes out as expected [51][56]. This provides further evidence that not only the band structure is reproduced at first glance, but also the wave functions are properly evaluated. This non-trivial example illustrates the

The effect of atmospheric doping on pressure-dependent Raman scattering in supported graphene

• Egor A. Kolesov,
• Mikhail S. Tivanov,
• Olga V. Korolik,
• Olesya O. Kapitanova,
• Xiao Fu,
• Hak Dong Cho,
• Tae Won Kang and
• Gennady N Panin

Beilstein J. Nanotechnol. 2018, 9, 704–710, doi:10.3762/bjnano.9.65

• and copper [19] which are terminated after the transfer. Besides, this may lead to different values of the average graphene–substrate distance resulting in deviation of the density of states (DOS) from a simple Dirac cone [16] and a consequent shift of the Dirac point energy, leading to different

• results in renormalization of the Fermi velocity, Dirac point velocity, and overall distortion of the Dirac cone [24], leading to a possible charge carrier density increase [25]. In the case of bilayer graphene, the desorption process leads to a density decrease of about 0.4 × 1013 cm−2 hole, which is

Transition from silicene monolayer to thin Si films on Ag(111): comparison between experimental data and Monte Carlo simulation

• Alberto Curcella,
• Romain Bernard,
• Yves Borensztein,
• Silvia Pandolfi and
• Geoffroy Prévot

Beilstein J. Nanotechnol. 2018, 9, 48–56, doi:10.3762/bjnano.9.7

• successive Si layers [23][24][25][26], with an interlayer spacing of ≈3Å. Such layers display an electronic band structure, measured by ARPES, that has been interpreted as a Dirac cone located 0.25 eV below the Fermi level [27]. These layers present a metallic behavior, with an electric conductivity one

3D continuum phonon model for group-IV 2D materials

• Morten Willatzen,
• Lok C. Lew Yan Voon,
• Appala Naidu Gandi and
• Udo Schwingenschlögl

Beilstein J. Nanotechnol. 2017, 8, 1345–1356, doi:10.3762/bjnano.8.136

• ]. In addition to obtaining a spectrum, it is often also useful to be able to predict and/or interpret properties of the spectrum based upon either microscopic or symmetric arguments. An excellent example is the prediction of a Dirac cone for silicene on the basis of symmetry [7] when DFT calculations

Interaction of iron phthalocyanine with the graphene/Ni(111) system

• Lorenzo Massimi,
• Simone Lisi,
• Daniela Pacilè,
• Carlo Mariani and
• Maria Grazia Betti

Beilstein J. Nanotechnol. 2014, 5, 308–312, doi:10.3762/bjnano.5.34

• Ir(111) represents two opposite sides of the graphene–metal interaction: a strong interaction with a strong modification of the free-standing graphene band structure is observed on Ni [11], while a low interaction with an almost unperturbed Dirac cone is present if graphene is grown on Ir [12][13