Thomas Stegmann
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View article: Electronic transport and anti-super-Klein tunneling in few-layer black phosphorous
Electronic transport and anti-super-Klein tunneling in few-layer black phosphorous Open
The electronic transport in few-layer black phosphorus (FLBP) nanoribbons is studied theoretically. The system is modeled on the basis of band-structures, which have been measured recently by $μ$-ARPES experiments. We show that the anisotr…
View article: Kekulé distortions in graphene on cadmium sulfide
Kekulé distortions in graphene on cadmium sulfide Open
The deposition of a two-dimensional material on the surface of a three-dimensional crystal can generate superlattices with electronic properties modified through the proximity spin-orbit effect. In this study, we found that Kekulé graphene…
View article: Edge-state transport in twisted bilayer graphene
Edge-state transport in twisted bilayer graphene Open
We investigate the electronic structure and transport properties of twisted bilayer graphene (TBLG) at a twist angle of $θ\approx 1.696\text{°}$. Using a combination of molecular dynamics and tight-binding calculations, we find two superla…
View article: Atomically Thin Current Pathways in Graphene through Kekulé-O Engineering
Atomically Thin Current Pathways in Graphene through Kekulé-O Engineering Open
We demonstrate that the current flow in graphene can be guided on atomically thin current pathways by the engineering of Kekulé-O distortions. A grain boundary in these distortions separates the system into topologically distinct regions a…
View article: Atomically thin current pathways in graphene through Kekulé-O engineering
Atomically thin current pathways in graphene through Kekulé-O engineering Open
We demonstrate that the current flow in graphene can be guided on atomically thin current pathways by means of the engineering of Kekulé-O distortions. A grain boundary in these distortions separates the system into topological distinct re…
View article: Electronic transport in bent carbon nanotubes
Electronic transport in bent carbon nanotubes Open
We study the electronic transport through uniformly bent carbon nanotubes. For this purpose, we describe the nanotube with the tight-binding model and calculate the local current flow by employing non-equilibrium Green's functions (NEGF) i…
View article: Graphene nanodrums as valleytronic devices
Graphene nanodrums as valleytronic devices Open
We investigate the electronic transport in graphene nanoelectromechanical resonators (GrNEMS), known also as graphene nanodrums or nanomembranes. We demonstrate that these devices, despite small values of out-of-plane strain, between $0.1$…
View article: Steering the current flow in twisted bilayer graphene
Steering the current flow in twisted bilayer graphene Open
A nanoelectronic device made of twisted bilayer graphene (TBLG) is proposed to steer the direction of the current flow. The ballistic electron current, injected at one edge of the bottom layer, can be guided predominantly to one of the lat…
View article: Valley-dependent time evolution of coherent electron states in tilted anisotropic Dirac materials
Valley-dependent time evolution of coherent electron states in tilted anisotropic Dirac materials Open
The effect of the Dirac cone tilt of anisotropic two-dimensional materials on\nthe time evolution of coherent electron states in the presence of electric and\nmagnetic fields is studied. We propose a canonical transformation that maps the\…
View article: Generalized Hamiltonian for Kekulé graphene and the emergence of valley-cooperative Klein tunneling
Generalized Hamiltonian for Kekulé graphene and the emergence of valley-cooperative Klein tunneling Open
We introduce a generalized Hamiltonian describing not only all topological phases observed experimentally in Kekulé graphene (KekGr) but predicting also new ones. These phases show features like a quadratic band crossing point, valley spli…
View article: Steering the current flow in twisted bilayer graphene
Steering the current flow in twisted bilayer graphene Open
A nanoelectronic device made of twisted bilayer graphene (TBLG) is proposed to steer the direction of the current flow. The ballistic electron current, injected at one edge of the bottom layer, can be guided predominantly to one of the lat…
View article: Hidden duality and accidental degeneracy in cycloacene and Möbius cycloacene
Hidden duality and accidental degeneracy in cycloacene and Möbius cycloacene Open
The accidental degeneracy appearing in cycloacenes as triplets and quadruplets is explained with the concept of segmentation, introduced here with the aim of describing the effective disconnection of π orbitals on these organic compounds. …
View article: Anomalous Floquet tunneling in uniaxially strained graphene
Anomalous Floquet tunneling in uniaxially strained graphene Open
The interplay of strain engineering and photon-assisted tunneling of\nelectrons in graphene is considered for giving rise to atypical transport\nphenomena. The combination of uniaxial strain and a time-periodic potential\nbarrier helps to …
View article: Hidden duality and accidental degeneracy in cycloacene and M\\"obius\n cycloacene
Hidden duality and accidental degeneracy in cycloacene and M\\"obius\n cycloacene Open
The accidental degeneracy appearing in cycloacenes as triplets and\nquadruplets is explained with the concept of segmentation, introduced here with\nthe aim of describing the effective disconnection of $\\pi$ orbitals on these\norganic com…
View article: Current vortices in aromatic carbon molecules
Current vortices in aromatic carbon molecules Open
International audience
View article: Electron Optics in Phosphorene pn Junctions: Negative Reflection and Anti-Super-Klein Tunneling
Electron Optics in Phosphorene pn Junctions: Negative Reflection and Anti-Super-Klein Tunneling Open
Ballistic electrons in phosphorene pn junctions show optical-like phenomena. Phosphorene is modeled by a tight-binding Hamiltonian that describes its electronic structure at low energies, where the electrons behave in the armchair directio…
View article: $\mathcal{PT}$-symmetric tight-binding chain with gain and loss: A completely solvable model
$\mathcal{PT}$-symmetric tight-binding chain with gain and loss: A completely solvable model Open
We present the analytical solution for the eigenvalues and eigenvectors of a $\mathcal{PT}$-symmetric tight-binding chain with gain and loss in a symmetric configuration. We show a simple method to predict the values of the parameters at w…
View article: Current Vortices in Aromatic Carbon Molecules
Current Vortices in Aromatic Carbon Molecules Open
The local current flow through three small aromatic carbon molecules, namely benzene, naphthalene and anthracene, is studied. Applying density functional theory and the non-equilibrium Green’s function method for transport, we demonstrate …
View article: Current Vortices in Aromatic Carbon Molecules
Current Vortices in Aromatic Carbon Molecules Open
The local current flow through three small aromatic carbon molecules, namely benzene, naphthalene and anthracene, is studied. Applying density functional theory and the non-equilibrium Green’s function method for transport, we demonstrate …
View article: Current splitting and valley polarization in elastically deformed graphene
Current splitting and valley polarization in elastically deformed graphene Open
Elastic deformations of graphene can significantly change the flow paths and valley polarization of the electric currents. We investigate these phenomena in graphene nanoribbons with localized out-of-plane deformations by means of tight-bi…
View article: Robustness of optimal transport in disordered interacting many-body networks
Robustness of optimal transport in disordered interacting many-body networks Open
The robustness of quantum transport under various perturbations is analyzed in disordered interacting many-body systems, which are constructed from the embedded Gaussian random matrix ensembles (EGEs). The transport efficiency can be enhan…
View article: Transport gap engineering by contact geometry in graphene nanoribbons: Experimental and theoretical studies on artificial materials
Transport gap engineering by contact geometry in graphene nanoribbons: Experimental and theoretical studies on artificial materials Open
Electron transport in small graphene nanoribbons is studied by microwave\nemulation experiments and tight-binding calculations. In particular, it is\ninvestigated under which conditions a transport gap can be observed. Our\nexperiments pro…
View article: Efficient quantum transport in disordered interacting many-body networks
Efficient quantum transport in disordered interacting many-body networks Open
The coherent transport of n fermions in disordered networks of l single-particle states connected by k-body interactions is studied. These networks are modeled by embedded Gaussian random matrix ensemble (EGE). The conductance bandwidth an…
View article: Benzene ring chains with lithium adsorption: Vibrations and their implications
Benzene ring chains with lithium adsorption: Vibrations and their implications Open
Lithium adsorption on aromatic molecules and polyacenes have been found to produce strong distortions associated to spontaneous symmetry breaking and lesser ones in more general cases. For polyphenyls we find similar, but more varied behav…