arXiv subjects

Jesús Arturo Sánchez-Sánchez

Publications and source records attributed to Jesús Arturo Sánchez-Sánchez.

4 recordsLinked to original sources

arXiv2025

Edge-state transport in gapped bilayer graphene

We investigate electronic transport in gapped bilayer graphene (gBLG) devices. For certain edge terminations -typically a combination of zigzag, armchair, and bearded types - we observe edge state conduction within the band gap, which is opened by a potential bias between the two layers. The edge states can generate a non-local resistance, in line with recent experiments [1]. Band structure calculations of gBLG nanoribbons corroborate the existence of the edge states, whose edge localization can be switched by tuning the electron energy. Their existence strongly depends on the edge termination and does not originate from a topological bulk-boundary correspondence.

cond-mat.mes-hall↗

arXiv2024

Edge-state transport in twisted bilayer graphene

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 superlattice gaps in the energy spectrum of the bulk, which emerge close to the Fermi level from the atomic rearrangement of the carbon atoms leading to a corrugation of the graphene sheets. Nanoribbons made from 1.696°-TBLG show edge-localized states inside the superlattice gaps. Applying the Green's function method, we demonstrate that the edge states carry electronic current with conductance values close to the conductance quantum. The edge states can generate a non-local resistance, which is not due to one-way transport at the edges but due to the fact that these states are localized only at certain edges of the system, depending on how the nanoribbon has been cut from the bulk.

cond-mat.mes-hall↗

arXiv2023

Spin-valley locking in Kekulé-distorted graphene with Dirac-Rashba interactions

The joint effects of Kekulé lattice distortions and Rashba-type spin-orbit coupling on the electronic properties of graphene are explored. We modeled the position dependence of the Rashba energy term in a manner that allows its seamless integration into the scheme introduced by Gamayun et al.[New J. Phys. 20, 023016 (2018)] to describe graphene with Kekulé lattice distortion. Particularly for the Kekulé-Y texture, the effective low energy Dirac Hamiltonian contains a new spin-valley locking term, in addition to the well-known Rashba-induced momentum-pseudospin and spin-pseudospin couplings, and the Kekulé-induced momentum-valley coupling term. We report on the low-energy band structure and Landau level spectra of Rashba-spin-orbit-coupled Kek-Y graphene, and propose an experimental scheme to discern between the presence of Rashba spin-orbit coupling, Kek-Y lattice distortion, and both, based on doping-dependent magnetotransport measurements.

cond-mat.mes-hall↗

arXiv2021

Steering the current flow in twisted bilayer graphene

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 lateral edges of the top layer. The current is steered to the opposite lateral edge, if either the twist angle is reversed or the electrons are injected in the valence band instead of the conduction band, making it possible to control the current flow by electric gates. When both graphene layers are aligned, the current passes straight through the system without changing its initial direction. The observed steering angle exceeds well the twist angle and emerges for a broad range of experimentally accessible parameters. It is explained by the trigonal shape of the energy bands beyond the van Hove singularity due to the Moiré interference pattern. As the shape of the energy bands depends on the valley degree of freedom, the steered current is partially valley polarized. Our findings show how to control and manipulate the current flow in TBLG. Technologically, they are of relevance for applications in twistronics and valleytronics.

cond-mat.mes-hall↗